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Edmund Jacobs
5 years ago
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1 !#! # %! <! doctype html public -//w3c//dtd html... > ' ()!* +, -.!/ *! * 1 <!DOCTYPE html PUBLIC -//W3C//DTD XHTML 1. Strict//EN <!DOCTYPE html PUBLIC -//W3C//DTD XHTML 1. Frameset//EN * %! * * * <!DOCTYPE html PUBLIC -//W3C//DTD XHTML 1. Transitional//EN Source: 5!*!! 6 4 *! * 8 97 *! 4! : * ' () 7;7 7<7 5 6 =* 6 = ) document.write ( hello ) document.bgcolor = blue > * 3! 5?! 5 '!! 4!! document.images[].src= newimage.gif document.forms[].introtext.value= how is life? 6 ) 1

?! 5 + 9. 5 * * 5 6 4!!! A! 5 4*!+4!!. 6!B9C ' 7 7 6!B9C B9C : 2! 6 * 22: 2!! 5 6! 9 ' <form name=form1.> <input type=text id=text1 > 6 D!; @ ; A * 77!!4 * ; 9* :! 4 ;+ <. ;!! 4 6 E:+:. 6 EA +A. 1 7!

2 ?! * * 5 6 4!!! A! 5 4*!+4!!. 6!B9C ' 7 7 6!B9C B9C : 2! 6 * 22: 2!! 5 6! 9 ' <form name=form1.> <input type=text id=text1 > 6 ; A * 77!!4 * ; 9* :! 4 ;+ <. ;!! 4 6 E:+:. 6 EA +A. 1 7! )7 5 <html> <head><title>dom-objects</title> <script>  </script> </head> <body> <form name=ourform > <input type=text id=firstname value=***** > <br /><input type=text id=lastname value=***** > <br /><select id=cities> <option value=nijmegen>nijmegen <option value=arnhem>arnhem <option value=madrid>madrid </select> <p><input type=button value=default values onclick= setdefaultvalues();> <input type=reset value=reset> </body></html> > 1G:+!. * document.getelementbyid() document.getelementsbyname() document.createnode() document.createtextnode() node.appendchild() node.setattribute( att, val ) node.style.<property>= value > +. E H = ) +H =.! > *! * I7! ! 4! *!! J *! 7I7! <.)3! H =!! function notempty ( elem ) { var str = elem.value; if ( str.length == ) { alert ( You must fill in all required fields (*)) ; return false ; else return true ; 2

There are two opportune times to perform validation checks: 1) when the user changes from one field to another and 2) when the user submits the data.

3 Example of how JavaScript can be used to check form data: : <script type= text/javascript > function checkname ( ) { if ( document.form1.yourname.value = ) { alert ( Enter your name ) ; return false ; else return true ; E! There are two opportune times to perform validation checks: 1) when the user changes from one field to another and 2) when the user submits the data. The Javascript events names for these cases are: onblur and onsubmit We will focus on the onsubmit event because it is the most commonly accepted time for validation. Generally we create a master function whose only purpose is to call other functions which do the actual checks to see if the form data is valid. : <form name= form1 onsubmit= return checkname(); > <input type= text id= yourname > ) +H <html> <head><title>form validation</title> <script type=text/javascript>  </script></head> <body> <form id=form1 onsubmit=return formvalidation( this );> First name:<br><input type=text id=firstname /> (*)<br /> Last name :<br><input type=text id=lastname /> (*) <p><input type=submit /> </body> </html> 1 +H <html><head><title>a form validation</title> <script type=text/javascript>  </script></head> <body onload=setfirstfocus ( )> <form name=ourform onsubmit=return validate ( this )> Firstname :<br /> <input type=text id=firstname size= 1> <br />Age (from 1 to 1): <br /><input type=text id=age size= 1> <br /><input type=submit value=submit> </body></html> K ' *!!!=!! L * L : A F M 3!!! +.4!6 I + *! >!!- *!> N H =H!=* 3* A O< *H 3=@!>, ' * +! ! P 6 3* *

4 Pages onload onunload Forms onsubmit onreset onselect J!* 3! 4 4 6! 6 3 1! Mouse Events onmouseover onmouseout onmouseup onmousedown onmousemove Elements onfocus element becomes active onblur element loses focus element is clicked once <form name= form1 onsubmit= return checkme() >.. <input type= button value= press onclick= clickfuntion( ) /> A! 4 7!! * 7 Method 1 (Link Events): Place an event handler as an attribute within a <...> tag Method 2 (Actions within FORMs): Place an (etc.) event handler inside a button type form element Method 3 (BODY onload onunload): E.g. use an event handler to ensure that all required objects are defined, with <html><head><title>event Examples</title> <script type=text/javascript>  </script></head> <body onload= loaded = true> <h1>onload amp; global variable</h1> <form> <input type=button value=press Me =if (loaded) doit ( );> <p>ex. with 'onchange'-method:</p> <input type=text value=??? onchange='checkfield ( this ); confirm (Continue?);' > <p>changing bgcolor:</p> <input type=button value=red =document.bgcolor = 'red'> <input type=button value=white =document.bgcolor = 'white'> <input type=button value=blue =document.bgcolor = 'blue'> <h4 =alert('you clicked on me!' ); >Click on me!</h4> </body></html> + 5. OBJECT Button element Checkbox Clickable ImageMap area Document Form Framesets Hypertext link Image Radio button Reset button Selection list Submit button TextArea element Text element Window EVENT HANDLERS AVAILABLE, onmouseover, onmouseout onload, onunload, onerror onsubmit, onreset onblur, onfocus, onmouseover, onmouseout onload, onerror, onabort onblur, onchange, onfocus onblur, onchange, onfocus, onselect onblur, onchange, onfocus, onselect onload, onunload, onblur, ;: D 8 Q!! <img src=../ Images/duck_pale.gif width=55 height= 7 onmouseover=src='../images/duck.gif'; onmouseout=src='../ Images/duck_pale.gif 44R > A * ) >! 1. Source: 4

5 : The following tables are taken from: Event #! Applies to Document body Document body Images, window Images Documents, images, links, text areas Documents, images, links, text areas Occurs when User loads the page in a browser User exits the page Error on loading an image or a window User aborts the loading of an image User depresses a key User releases a key Handler #! :: Event ' % % Applies to Documents, images, links, text areas Text fields, text areas, select lists Documents, buttons, links Documents, buttons, links Buttons, radio buttons, checkboxes, submit buttons, reset buttons, links Links Areas, links Occurs when User presses or holds down a key User changes the value of an element User depresses a mouse button User releases a mouse button User clicks a form element or link User moves cursor over a link User moves cursor out of an image map or link Handler ' % % ::: Event *, + ( *! () Applies to Text fields, text areas Windows and all form elements Windows and all form elements Forms Forms Windows Windows Windows Occurs when User selects form element s input field User gives element input focus User moves focus to some other element User clicks a Reset button User clicks a Submit button User or script moves a window User or script resizes a window User drops an object onto the browser window Handler *, + ( *! () <html><head><title>some events</title> <script type=text/javascript>  </script> </head> <body onload= changetitle();> <h3 id=title1 onmouseover=style.color='red'; onmouseout=style.color='black';>on events</h3> <form action=> <input type=button value=greet the world onclick=alert ('Hello world'); /> <p /><input type=button value=change Title onclick= changetitle( ) /> </body></html> 1 5 > 5 Objects have attributes and methods Many pre-defined objects and object types Using objects follows the syntax of C++/Java: objectname.attributename objectname.methodname() Arrays and their methods Strings and their methods 1 5 1! var a = [ 8, 7, 6, 5 ] ; for ( i= ; i < a.length ; i++ ) a [ i ] += 2 ; var b = a.reverse( ) ; 5

! 5 44 # %@ 4 Example: METHOD NAME EXAMPLE var mystr = Let's see what happens!; RETURNED VALUE charat mystr.charat() L mystr.charat(1) w indexof mystr.indexof(at) 12 mystr.indexof(e) 1 mystr.

6 ! 5 44 # %@ 4 Example: METHOD NAME EXAMPLE var mystr = Let's see what happens!; RETURNED VALUE charat mystr.charat() L mystr.charat(1) w indexof mystr.indexof(at) 12 mystr.indexof(e) 1 mystr.indexof(e, 2) 7 lastindexof mystr.lastindexof(a) 16 mystr.lastindexof(a, 14) 12 substring mystr.substring(, 7) Let's s mystr.substring(7, ) Let's s mystr.substring(, 5) Let's see what happens! mystr.substring() Let's see what happens! mystr.substring(4) s see what happens! length mystr.length 23 mystr.substring(, 7).length 7 Source: 1 > S9 1,> *** *(! 1 T ' * 5R.! * 5R!! 3 +53* 53. : R > H = * 3! R5* N! 5* ;< ST5N 5R5;< ;S5N R* R5N 5!+.5 N * 5 53 N = 5!5!N! U5!,<B!C N!! 5!+5 NR9<U!9O. 5N! H=! 6

CISH-6510 Web Application Design and Development. Overview of JavaScript. Overview

CISH-6510 Web Application Design and Development Overview of JavaScript Overview What is JavaScript? History Uses of JavaScript Location of Code Simple Alert Example Events Events Example Color Example