JavaScript and PHP. JavaScript and PHP. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

Transcription

1 JavaScript and PHP DD1335 (Lecture 8) Basic Internet Programming Spring / 26

2 A little about JavaScript DD1335 (Lecture 8) Basic Internet Programming Spring / 26

3 JavaScript What is it good for? DD1335 (Lecture 8) Basic Internet Programming Spring / 26

4 JavaScript What is it good for? JavaScript is a general programming language meant to be embedded into HTML pages to enhance the code and to add dynamics to the normally static content of HTML pages. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

5 JavaScript What is it good for? JavaScript is a general programming language meant to be embedded into HTML pages to enhance the code and to add dynamics to the normally static content of HTML pages. It may be used for everything that HTML is used for and much more and it is meant to execute on the client side. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

6 JavaScript What is it good for? JavaScript is a general programming language meant to be embedded into HTML pages to enhance the code and to add dynamics to the normally static content of HTML pages. It may be used for everything that HTML is used for and much more and it is meant to execute on the client side. However, CSS manages most of the problems that JavaScript can manage, so today there are not many reasons left to use it. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

7 JavaScript What is it good for? JavaScript is a general programming language meant to be embedded into HTML pages to enhance the code and to add dynamics to the normally static content of HTML pages. It may be used for everything that HTML is used for and much more and it is meant to execute on the client side. However, CSS manages most of the problems that JavaScript can manage, so today there are not many reasons left to use it. Some small tasks are still best taken care of by JavaScript. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

8 JavaScript What is it good for? JavaScript is a general programming language meant to be embedded into HTML pages to enhance the code and to add dynamics to the normally static content of HTML pages. It may be used for everything that HTML is used for and much more and it is meant to execute on the client side. However, CSS manages most of the problems that JavaScript can manage, so today there are not many reasons left to use it. Some small tasks are still best taken care of by JavaScript. NOTE! JavaScript is case sensitive DD1335 (Lecture 8) Basic Internet Programming Spring / 26

9 JavaScript a universal programming language DD1335 (Lecture 8) Basic Internet Programming Spring / 26

10 JavaScript a universal programming language You can do all kinds of tasks with JavaScript. The special version that is embedded into browsers have some special features though. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

11 JavaScript a universal programming language You can do all kinds of tasks with JavaScript. The special version that is embedded into browsers have some special features though. It has features to reach all objects and parameters of web pages. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

12 JavaScript a universal programming language You can do all kinds of tasks with JavaScript. The special version that is embedded into browsers have some special features though. It has features to reach all objects and parameters of web pages. JavaScript has nothing to do with Java. It originated as LiveScript and changed name for marketing purposes. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

13 JavaScript a universal programming language You can do all kinds of tasks with JavaScript. The special version that is embedded into browsers have some special features though. It has features to reach all objects and parameters of web pages. JavaScript has nothing to do with Java. It originated as LiveScript and changed name for marketing purposes. Most language constructions are as in Java but a weak type system that allows all kinds of values to be bound to a variable: DD1335 (Lecture 8) Basic Internet Programming Spring / 26

14 JavaScript a universal programming language You can do all kinds of tasks with JavaScript. The special version that is embedded into browsers have some special features though. It has features to reach all objects and parameters of web pages. JavaScript has nothing to do with Java. It originated as LiveScript and changed name for marketing purposes. Most language constructions are as in Java but a weak type system that allows all kinds of values to be bound to a variable: var a, s = 3; may be followed by s = "hello"; DD1335 (Lecture 8) Basic Internet Programming Spring / 26

15 JavaScript a universal programming language You can do all kinds of tasks with JavaScript. The special version that is embedded into browsers have some special features though. It has features to reach all objects and parameters of web pages. JavaScript has nothing to do with Java. It originated as LiveScript and changed name for marketing purposes. Most language constructions are as in Java but a weak type system that allows all kinds of values to be bound to a variable: var a, s = 3; may be followed by s = "hello"; Here, variables a and s have been declared and an initial value has been assigned to s. Then s has been given a value of a different type. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

16 Mandatory Hello World JavaScript program DD1335 (Lecture 8) Basic Internet Programming Spring / 26

17 Mandatory Hello World JavaScript program <html> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

18 Mandatory Hello World JavaScript program <html> <head> <title>hello World</title> </head> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

19 Mandatory Hello World JavaScript program <html> <head> <title>hello World</title> </head> <body> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

20 Mandatory Hello World JavaScript program <html> <head> <title>hello World</title> </head> <body> <script type="text/javascript"> </script> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

21 Mandatory Hello World JavaScript program <html> <head> <title>hello World</title> </head> <body> <script type="text/javascript"> document.writeln("hello World"); </script> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

22 JavaScript... JavaScript and PHP DD1335 (Lecture 8) Basic Internet Programming Spring / 26

23 JavaScript... JavaScript and PHP No need to use semicolon ( ; ) unless you put more than one statement on the same line. But as you may end statements with a semicolon, it s best to allways do it. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

24 JavaScript... No need to use semicolon ( ; ) unless you put more than one statement on the same line. But as you may end statements with a semicolon, it s best to allways do it. Strings may be enclosed in quotes ( " ) or in apostrophes ( ) allowing for simple inclusion of these into strings. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

25 JavaScript... No need to use semicolon ( ; ) unless you put more than one statement on the same line. But as you may end statements with a semicolon, it s best to allways do it. Strings may be enclosed in quotes ( " ) or in apostrophes ( ) allowing for simple inclusion of these into strings. var s1 = "it s rather cold today"; var s2 = so the "goblins" stay in their caves ; DD1335 (Lecture 8) Basic Internet Programming Spring / 26

26 JavaScript... No need to use semicolon ( ; ) unless you put more than one statement on the same line. But as you may end statements with a semicolon, it s best to allways do it. Strings may be enclosed in quotes ( " ) or in apostrophes ( ) allowing for simple inclusion of these into strings. var s1 = "it s rather cold today"; var s2 = so the "goblins" stay in their caves ; The string var s3 = s1 + s2; will contain the value it s rather cold today so the "goblins" stay in their caves DD1335 (Lecture 8) Basic Internet Programming Spring / 26

27 JavaScript... JavaScript and PHP You may put your script anywhere in the HTML page but the normal is to put declarations in the <head>...</head> part and the rest exactly where you want things to happen. To check what i mentioned in the previous slide you may put the following in a file (the name ending with.html ): DD1335 (Lecture 8) Basic Internet Programming Spring / 26

28 JavaScript... JavaScript and PHP You may put your script anywhere in the HTML page but the normal is to put declarations in the <head>...</head> part and the rest exactly where you want things to happen. To check what i mentioned in the previous slide you may put the following in a file (the name ending with.html ): <html> <head> <script type="text/javascript"> var s1 = "it s rather cold today"; var s2 = so the "goblins" stay in their caves ; </script> <title>testing javascript strings</title> </head> <body> <script type="text/javascript"> document.write(s1 + s2); </script> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

29 Find out if JavaScript is turned on (or not available) If you want to use JavaScript in a page, JavaScript must be enabled in the browser. There are no means to ask the browser if JavaScript is enabled, but you may have a page using JavaScript to redirect the user to the real web page and, in case it doesn t work, issue an error message. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

30 Find out if JavaScript is turned on (or not available) If you want to use JavaScript in a page, JavaScript must be enabled in the browser. There are no means to ask the browser if JavaScript is enabled, but you may have a page using JavaScript to redirect the user to the real web page and, in case it doesn t work, issue an error message. <html> <head> <title>javascript test</title> <script type="text/javascript"> location= start.html ; </script> </head> <body> <h4>sorry, JavaScript is not enabled in your browser!</h4> To visit this site, enable JavaScript and then reload this page. </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

31 Hiding JavaScript from not enabled browsers <html> <head> <title>hello World</title> </head> <body> <script type="text/javascript"> <!-- document.writeln("hello World"); // --> </script> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

32 Checking for JavaScript in enabled browsers <html> <head> <title>checking if JavaScript is on</title> </head> <body> <script type="text/javascript"> <!-- // your JavaScript code here // --> </script> <noscript> Your browser understands JavaScript. However, the feature is turned off. Please turn it on to enjoy the full capability of this page. </noscript> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

33 Using JavaScript in modern HTML As said, most things that JavaScript can do, are better performed by server side languages, so let s focus on things that are more convenient to do on the client side, e.g. using navigation history or perform form input control. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

34 Using JavaScript in modern HTML As said, most things that JavaScript can do, are better performed by server side languages, so let s focus on things that are more convenient to do on the client side, e.g. using navigation history or perform form input control. Using JavaScript to navigate <html> <head> <title>going back to the previous page</title> </head. <body> The password you typed in is not long enough. Please <a href="javascript:history.back()">go back</a> to correct it. </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

35 Using JavaScript to navigate... <html> <head> <title>going n pages back </title> </head> <body> Click <a href="javascript:history.go(-3)">here</a> to go back to the the beginning of the entry form. </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

36 Using JavaScript to navigate... <html> <head> <title>going n pages back </title> </head> <body> Click <a href="javascript:history.go(-3)">here</a> to go back to the the beginning of the entry form. </body> </html> <html> <head> <title>moving forward</title> </head> <body> Click <a href="javascript:history.go(1)">here</a> to move forward. </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

37 Using JavaScript to navigate... <html> <head> <title>navigating to a CSC course</title> </head> <body> Please select one of the courses below <br /> <form> <select onchange="location= + this.options[this.selectedindex].value"> <option>select a course</option> <option value="dd1334/dbtek10/">dbtek10</option> <option value="dd1335/gruint10/">gruint10</option> <option value="dd2471/moddb10/">moddb10</option> </select> </form> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

38 Using JavaScript for form input control First we need some basic functions. In the following i omit the <script type="text/javascript"> </script> part as it is obvious that all functions have to be declared inside a script. The isempty function function isempty(str) { if (str == null str == "") return true; return false; } DD1335 (Lecture 8) Basic Internet Programming Spring / 26

39 Using JavaScript for form input control... The trim function function trim(str) { if (str!=null) { while (str.length > 0 && str.charat(str.length - 1) == " ") str = str.substring(0, str.length - 1); while (str.length > 0 && str.charat(0) == " ") str = str.substring(1, str.length); } return str; } Form validating function function validateform(theform) { if (isempty(trim(theform.username.value))) { alert( Please enter a valid name ); return false; } if (isempty(trim(theform.passwd.value))) { alert( Please enter a valid password ); return false; } return true; } DD1335 (Lecture 8) Basic Internet Programming Spring / 26

40 Using JavaScript for form input control... <html> <head><title>form Validation</title> <script type="text/javascript"> // Here is the place for the functions from previous slides </script> </head> <body> <form method="post" action="enter.html" onsubmit= return validateform(this) > <table> <tr><td>name:</td> <td><input type="text" name="username"></td></tr> <tr><td>password:</td> <td><input type="password" name="passwd"></td></tr> <tr><td colspan="2" align="right"> <input type="submit"></td></tr> </table> </form> </body> </html> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

41 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

42 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language DD1335 (Lecture 8) Basic Internet Programming Spring / 26

43 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast DD1335 (Lecture 8) Basic Internet Programming Spring / 26

44 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast Problems when size and complexity grow DD1335 (Lecture 8) Basic Internet Programming Spring / 26

45 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast Problems when size and complexity grow Performance penalty (though addressed in the Zend engine) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

46 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast Problems when size and complexity grow Performance penalty (though addressed in the Zend engine) A number of PHP organisations and hosting services around the net DD1335 (Lecture 8) Basic Internet Programming Spring / 26

47 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast Problems when size and complexity grow Performance penalty (though addressed in the Zend engine) A number of PHP organisations and hosting services around the net A huge catalogue of features developed by volunteers DD1335 (Lecture 8) Basic Internet Programming Spring / 26

48 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast Problems when size and complexity grow Performance penalty (though addressed in the Zend engine) A number of PHP organisations and hosting services around the net A huge catalogue of features developed by volunteers Language in evolution... PHP 5 adds exception handling. OOP is also an add-on: Introduced in PHP4, perfected in PHP5 DD1335 (Lecture 8) Basic Internet Programming Spring / 26

49 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast Problems when size and complexity grow Performance penalty (though addressed in the Zend engine) A number of PHP organisations and hosting services around the net A huge catalogue of features developed by volunteers Language in evolution... PHP 5 adds exception handling. OOP is also an add-on: Introduced in PHP4, perfected in PHP5 most OOP concepts and keywords are as in java: class, extends, interface, private, protected, etc DD1335 (Lecture 8) Basic Internet Programming Spring / 26

50 Quick overview of PHP What is PHP PHP: Hypertext Processor (or Personal Home Page?) Interpreted language Easy to get something done fast Problems when size and complexity grow Performance penalty (though addressed in the Zend engine) A number of PHP organisations and hosting services around the net A huge catalogue of features developed by volunteers Language in evolution... PHP 5 adds exception handling. OOP is also an add-on: Introduced in PHP4, perfected in PHP5 most OOP concepts and keywords are as in java: class, extends, interface, private, protected, etc exceptions are as in Java (try/catch, etc) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

51 What can PHP do? JavaScript and PHP CGI scripting of course DD1335 (Lecture 8) Basic Internet Programming Spring / 26

52 What can PHP do? CGI scripting of course Based on escapes within HTML pages <?php...?> or <%... %> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

53 What can PHP do? CGI scripting of course Based on escapes within HTML pages <?php...?> or <%... %> Command line scripting DD1335 (Lecture 8) Basic Internet Programming Spring / 26

54 What can PHP do? CGI scripting of course Based on escapes within HTML pages <?php...?> or <%... %> Command line scripting GUI applications (PHP-GTK) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

55 Installation JavaScript and PHP Install the PHP interpreter separately. There is good support for this in Linux DD1335 (Lecture 8) Basic Internet Programming Spring / 26

56 Installation Install the PHP interpreter separately. There is good support for this in Linux In the webserver configuration, associate the php extension with the PHP interpreter DD1335 (Lecture 8) Basic Internet Programming Spring / 26

57 Installation Install the PHP interpreter separately. There is good support for this in Linux In the webserver configuration, associate the php extension with the PHP interpreter For serious applications you will need a database engine DD1335 (Lecture 8) Basic Internet Programming Spring / 26

58 Installation Install the PHP interpreter separately. There is good support for this in Linux In the webserver configuration, associate the php extension with the PHP interpreter For serious applications you will need a database engine Apache is the typical choice for the web server. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

59 Installation Install the PHP interpreter separately. There is good support for this in Linux In the webserver configuration, associate the php extension with the PHP interpreter For serious applications you will need a database engine Apache is the typical choice for the web server. Integrated as a module, so no supplementary processes are created (in CGI, typically there is one process per access, which is very expensive) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

60 Installation Install the PHP interpreter separately. There is good support for this in Linux In the webserver configuration, associate the php extension with the PHP interpreter For serious applications you will need a database engine Apache is the typical choice for the web server. Integrated as a module, so no supplementary processes are created (in CGI, typically there is one process per access, which is very expensive) Mysql or PostgreSQL is the typical db engine DD1335 (Lecture 8) Basic Internet Programming Spring / 26

61 Installation Install the PHP interpreter separately. There is good support for this in Linux In the webserver configuration, associate the php extension with the PHP interpreter For serious applications you will need a database engine Apache is the typical choice for the web server. Integrated as a module, so no supplementary processes are created (in CGI, typically there is one process per access, which is very expensive) Mysql or PostgreSQL is the typical db engine Most MS Windows users prefer Mysql DD1335 (Lecture 8) Basic Internet Programming Spring / 26

62 Installation Install the PHP interpreter separately. There is good support for this in Linux In the webserver configuration, associate the php extension with the PHP interpreter For serious applications you will need a database engine Apache is the typical choice for the web server. Integrated as a module, so no supplementary processes are created (in CGI, typically there is one process per access, which is very expensive) Mysql or PostgreSQL is the typical db engine Most MS Windows users prefer Mysql I d choose PostgreSQL as it is more complete in terms of functionality DD1335 (Lecture 8) Basic Internet Programming Spring / 26

63 PHP in HTML JavaScript and PHP The most frequent use of PHP is in scripts embedded in web pages DD1335 (Lecture 8) Basic Internet Programming Spring / 26

64 PHP in HTML The most frequent use of PHP is in scripts embedded in web pages Escaping follows the same rules as in ASP and JSP <?php...?>, <?...?>, <%... %>, <%=.... %> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

65 PHP in HTML The most frequent use of PHP is in scripts embedded in web pages Escaping follows the same rules as in ASP and JSP <?php...?>, <?...?>, <%... %>, <%=.... %> As in JSP, escaping can be interrupted to write some HTML <?php if ($expression) {?> <b>this is true.</b> <?php }?> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

66 PHP in HTML The most frequent use of PHP is in scripts embedded in web pages Escaping follows the same rules as in ASP and JSP <?php...?>, <?...?>, <%... %>, <%=.... %> As in JSP, escaping can be interrupted to write some HTML <?php if ($expression) {?> <b>this is true.</b> <?php }?> You can see the evolution under community pressure, here and in other areas DD1335 (Lecture 8) Basic Internet Programming Spring / 26

67 PHP in HTML The most frequent use of PHP is in scripts embedded in web pages Escaping follows the same rules as in ASP and JSP <?php...?>, <?...?>, <%... %>, <%=.... %> As in JSP, escaping can be interrupted to write some HTML <?php if ($expression) {?> <b>this is true.</b> <?php }?> You can see the evolution under community pressure, here and in other areas Though it is possible to use <script language="php" >...</script>, don t... DD1335 (Lecture 8) Basic Internet Programming Spring / 26

68 PHP in HTML JavaScript and PHP The most frequent use of PHP is in scripts embedded in web pages Escaping follows the same rules as in ASP and JSP <?php...?>, <?...?>, <%... %>, <%=.... %> As in JSP, escaping can be interrupted to write some HTML <?php if ($expression) {?> <b>this is true.</b> <?php }?> You can see the evolution under community pressure, here and in other areas Though it is possible to use <script language="php" >...</script>, don t... the language attribute is deprecated DD1335 (Lecture 8) Basic Internet Programming Spring / 26

69 PHP in HTML JavaScript and PHP The most frequent use of PHP is in scripts embedded in web pages Escaping follows the same rules as in ASP and JSP <?php...?>, <?...?>, <%... %>, <%=.... %> As in JSP, escaping can be interrupted to write some HTML <?php if ($expression) {?> <b>this is true.</b> <?php }?> You can see the evolution under community pressure, here and in other areas Though it is possible to use <script language="php" >...</script>, don t... the language attribute is deprecated PHP is a server side language and the <script> tag is for client side processing DD1335 (Lecture 8) Basic Internet Programming Spring / 26

70 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

71 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript DD1335 (Lecture 8) Basic Internet Programming Spring / 26

72 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

73 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string DD1335 (Lecture 8) Basic Internet Programming Spring / 26

74 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes DD1335 (Lecture 8) Basic Internet Programming Spring / 26

75 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes DD1335 (Lecture 8) Basic Internet Programming Spring / 26

76 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes $a.$b appends the string b and at the end of the string a DD1335 (Lecture 8) Basic Internet Programming Spring / 26

77 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes $a.$b appends the string b and at the end of the string a $a(index1, index2) gives a substring DD1335 (Lecture 8) Basic Internet Programming Spring / 26

78 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes $a.$b appends the string b and at the end of the string a $a(index1, index2) gives a substring string functions in the function library DD1335 (Lecture 8) Basic Internet Programming Spring / 26

79 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes $a.$b appends the string b and at the end of the string a $a(index1, index2) gives a substring string functions in the function library arrays are mappings between keys and values (Dictionary/Hashtable/Map in java) $arr = array("foo" => "bar", 12 => true) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

80 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes $a.$b appends the string b and at the end of the string a $a(index1, index2) gives a substring string functions in the function library arrays are mappings between keys and values (Dictionary/Hashtable/Map in java) $arr = array("foo" => "bar", 12 => true) Automactic type conversions between types (very dangerous...). Explicit type conversions exist too DD1335 (Lecture 8) Basic Internet Programming Spring / 26

81 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes $a.$b appends the string b and at the end of the string a $a(index1, index2) gives a substring string functions in the function library arrays are mappings between keys and values (Dictionary/Hashtable/Map in java) $arr = array("foo" => "bar", 12 => true) Automactic type conversions between types (very dangerous...). Explicit type conversions exist too Classes and objects, OOP DD1335 (Lecture 8) Basic Internet Programming Spring / 26

82 Types JavaScript and PHP A variable name begins with $, no type declaration (type declarations can be required by passing some settings to the interpreter) weak type system as in JavaScript boolean, integer, float, though internally all numbers are floats. string single-quoted, no character escapes double-quoted, with character escapes $a.$b appends the string b and at the end of the string a $a(index1, index2) gives a substring string functions in the function library arrays are mappings between keys and values (Dictionary/Hashtable/Map in java) $arr = array("foo" => "bar", 12 => true) Automactic type conversions between types (very dangerous...). Explicit type conversions exist too Classes and objects, OOP Resources, a kind of reference DD1335 (Lecture 8) Basic Internet Programming Spring / 26

83 Variables JavaScript and PHP See Types DD1335 (Lecture 8) Basic Internet Programming Spring / 26

84 Variables See Types Assignment by value (not by reference) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

85 Variables See Types Assignment by value (not by reference) Lots of predefined variables, especially related to HTTP/CGI DD1335 (Lecture 8) Basic Internet Programming Spring / 26

86 Variables See Types Assignment by value (not by reference) Lots of predefined variables, especially related to HTTP/CGI _SERVER, _GET, _POST, _COOKIE, _FILES, _REQUEST, _SESSION DD1335 (Lecture 8) Basic Internet Programming Spring / 26

87 Variables See Types Assignment by value (not by reference) Lots of predefined variables, especially related to HTTP/CGI _SERVER, _GET, _POST, _COOKIE, _FILES, _REQUEST, _SESSION External variables, useful for forms DD1335 (Lecture 8) Basic Internet Programming Spring / 26

88 Variables See Types Assignment by value (not by reference) Lots of predefined variables, especially related to HTTP/CGI _SERVER, _GET, _POST, _COOKIE, _FILES, _REQUEST, _SESSION External variables, useful for forms Functions as variables DD1335 (Lecture 8) Basic Internet Programming Spring / 26

89 Other procedural stuff JavaScript and PHP Operators similar to Java DD1335 (Lecture 8) Basic Internet Programming Spring / 26

90 Other procedural stuff JavaScript and PHP Operators similar to Java Statements similar to Java, plus: DD1335 (Lecture 8) Basic Internet Programming Spring / 26

91 Other procedural stuff JavaScript and PHP Operators similar to Java Statements similar to Java, plus: <? if(...) :?>...<? endif;?> DD1335 (Lecture 8) Basic Internet Programming Spring / 26

92 Other procedural stuff JavaScript and PHP Operators similar to Java Statements similar to Java, plus: <? if(...) :?>...<? endif;?> foreach () through arrays, just values, or also keys DD1335 (Lecture 8) Basic Internet Programming Spring / 26

93 Other procedural stuff JavaScript and PHP Operators similar to Java Statements similar to Java, plus: <? if(...) :?>...<? endif;?> foreach () through arrays, just values, or also keys foreach (array_expression as $value) statement DD1335 (Lecture 8) Basic Internet Programming Spring / 26

94 Other procedural stuff JavaScript and PHP Operators similar to Java Statements similar to Java, plus: <? if(...) :?>...<? endif;?> foreach () through arrays, just values, or also keys foreach (array_expression as $value) statement foreach (array_expression as $key => $value) statement DD1335 (Lecture 8) Basic Internet Programming Spring / 26

95 Other procedural stuff JavaScript and PHP Operators similar to Java Statements similar to Java, plus: <? if(...) :?>...<? endif;?> foreach () through arrays, just values, or also keys foreach (array_expression as $value) statement foreach (array_expression as $key => $value) statement Code inclusion with require() and include() DD1335 (Lecture 8) Basic Internet Programming Spring / 26

96 Other procedural stuff JavaScript and PHP Operators similar to Java Statements similar to Java, plus: <? if(...) :?>...<? endif;?> foreach () through arrays, just values, or also keys foreach (array_expression as $value) statement foreach (array_expression as $key => $value) statement Code inclusion with require() and include() Conditional function definition (similar to C #ifdef ) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

97 Features JavaScript and PHP HTTP authentication, cookies, file uploads DD1335 (Lecture 8) Basic Internet Programming Spring / 26

98 Features JavaScript and PHP HTTP authentication, cookies, file uploads Remote files (like java.net.urlconnection) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

99 Features JavaScript and PHP HTTP authentication, cookies, file uploads Remote files (like java.net.urlconnection) Connections (like java.net.socket) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

100 Features JavaScript and PHP HTTP authentication, cookies, file uploads Remote files (like java.net.urlconnection) Connections (like java.net.socket) Persistent db connections DD1335 (Lecture 8) Basic Internet Programming Spring / 26

101 Features JavaScript and PHP HTTP authentication, cookies, file uploads Remote files (like java.net.urlconnection) Connections (like java.net.socket) Persistent db connections Normally db connections are defined with engine specific functions as external resources. Each access would open its connection, which is expensive. So applications with extensive use of databases had better use Java or pay a heavy performance penalty. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

102 Functions JavaScript and PHP Array functions, calendar fuctions, date functions, character functions, IO functions, printer, file/directory, etc DD1335 (Lecture 8) Basic Internet Programming Spring / 26

103 Functions Array functions, calendar fuctions, date functions, character functions, IO functions, printer, file/directory, etc Functions for protocols/standards, e.g. FTP, HTTP, URL, LDAP, IRC, Mail, NSAPI, popmail, XML/XSL, Bzip2/Zip/Zlib DD1335 (Lecture 8) Basic Internet Programming Spring / 26

104 Functions Array functions, calendar fuctions, date functions, character functions, IO functions, printer, file/directory, etc Functions for protocols/standards, e.g. FTP, HTTP, URL, LDAP, IRC, Mail, NSAPI, popmail, XML/XSL, Bzip2/Zip/Zlib Functions for various databases (Mysql, Oracle, MS SQL server, msql, PostgreSQL, SQLite, dbase), dbx is general DD1335 (Lecture 8) Basic Internet Programming Spring / 26

105 Functions Array functions, calendar fuctions, date functions, character functions, IO functions, printer, file/directory, etc Functions for protocols/standards, e.g. FTP, HTTP, URL, LDAP, IRC, Mail, NSAPI, popmail, XML/XSL, Bzip2/Zip/Zlib Functions for various databases (Mysql, Oracle, MS SQL server, msql, PostgreSQL, SQLite, dbase), dbx is general Functions for other systems/tools: e.g. Apache, COM, Cyrus, PDF, dbase, DBM, DOM,.NET, Lotus Notes, GNU readline, Hyperware DD1335 (Lecture 8) Basic Internet Programming Spring / 26

106 Conclusions JavaScript and PHP Easy to learn from Java or C DD1335 (Lecture 8) Basic Internet Programming Spring / 26

107 Conclusions JavaScript and PHP Easy to learn from Java or C CGI parameters, HTTP sessions, etc are easy to recognize DD1335 (Lecture 8) Basic Internet Programming Spring / 26

108 Conclusions JavaScript and PHP Easy to learn from Java or C CGI parameters, HTTP sessions, etc are easy to recognize Good language/system for doing something small fast (but then JSP/ASP do most of the same) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

109 Conclusions JavaScript and PHP Easy to learn from Java or C CGI parameters, HTTP sessions, etc are easy to recognize Good language/system for doing something small fast (but then JSP/ASP do most of the same) Not a wise choice for a serious/large project due to the lack of type safety, lack of OOP in the libraries, etc. DD1335 (Lecture 8) Basic Internet Programming Spring / 26

110 Conclusions JavaScript and PHP Easy to learn from Java or C CGI parameters, HTTP sessions, etc are easy to recognize Good language/system for doing something small fast (but then JSP/ASP do most of the same) Not a wise choice for a serious/large project due to the lack of type safety, lack of OOP in the libraries, etc. Experienced PHP people confirm that larger projects tend to become a big mess due to the freedoms that seemed so good in the begining, which make programmers lazy DD1335 (Lecture 8) Basic Internet Programming Spring / 26

111 Conclusions JavaScript and PHP Easy to learn from Java or C CGI parameters, HTTP sessions, etc are easy to recognize Good language/system for doing something small fast (but then JSP/ASP do most of the same) Not a wise choice for a serious/large project due to the lack of type safety, lack of OOP in the libraries, etc. Experienced PHP people confirm that larger projects tend to become a big mess due to the freedoms that seemed so good in the begining, which make programmers lazy The array concept is nice, but its name is misleading (array means something very different in the rest of the field of Computer Science) DD1335 (Lecture 8) Basic Internet Programming Spring / 26

112 Conclusions JavaScript and PHP Easy to learn from Java or C CGI parameters, HTTP sessions, etc are easy to recognize Good language/system for doing something small fast (but then JSP/ASP do most of the same) Not a wise choice for a serious/large project due to the lack of type safety, lack of OOP in the libraries, etc. Experienced PHP people confirm that larger projects tend to become a big mess due to the freedoms that seemed so good in the begining, which make programmers lazy The array concept is nice, but its name is misleading (array means something very different in the rest of the field of Computer Science) Still, a very good choice for pragmatists DD1335 (Lecture 8) Basic Internet Programming Spring / 26