JAVASCRIPT BASICS. JavaScript String Functions. Here is the basic condition you have to follow. If you start a string with

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Clementine Marsh
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1 JavaScript String Functions Description String constants can be specified by enclosing characters or strings within double quotes, e.g. "WikiTechy is the best site to learn JavaScript". A string constant or string characters is technically an array of characters that is terminated by a null character '\0' at the end. Technically, the memory space required to represent or store a string of length n is actually n+1. This helps us to understand the end of the string as we are aware of the string will be terminated by a null character (so we know when they stop). For declaration and manipulating the strings in JavaScript, always write them with single quotes ' or double quotes around them. This enables or advises the browser to understand that, it's dealing with a string. Here is the basic condition you have to follow. If you start a string with a single quote and end it with a double quote, JavaScript won t understand what it means. As a rule, if you are using single quotes ' then you have end up with single quotes. The same thing for double quotes too. Start and end up with Double quotes.

2 Below is the list of basic JavaScript string functions to be noted down Concatenating strings (+) Concatenating or Joining two or more strings. It returns a string. indexof indexof - Find a character and its occurrences in a string. It returns an integer var a = Welcome to wikitechy JavaScript world!'; document.write(a.indexof('y')) This will return, 19. Start counting from 0,1 you will get it. lastindexof lastindexof - Find a character and its last occurrences in a string. It returns an integer var a = Welcome to wikitechy JavaScript world!'; document.write(a. lastindexof ('e')) This will return, 16. Start counting from 0,1 you will get it.

3 charat charat Gives the character at the particular location. Input parameter is a number to this method and it returns the character. var b = 'learn JavaScript step by step;' document.write(b.charat(4)) This will return, n. Start counting from 0,1 you will get it. Length Length Provides the length of the string. It returns an integer. var b ='learn JavaScript basics'; document.write(b.length); This will return, 23. Split Split This function splits up the string and provides an array of string which you can access through its array index. var val = WikiTechy javascript for beginners' var temp = new Array(); temp = val.split(' ');

4 Substring This will return the string as temp[0] = 'WikiTechy'; temp[1] = 'javascript'; temp[2] = 'for'; temp[3] = beginners'; Substring - Get the substring in a string. This will return a string. var a = WikiTechy JavaScript for beginners' document.write(a.substring(2)); itechy javascript for beginners Another way of specifying the substring (first_index, last_index). var a = WikiTechy javascript' document.write(a.substring(4,10)); Techy j

5 Substr Substr This method substr() will works slightly differently. Instead of the second number being an index number, it gives the number of characters. The format is substring (first_index, length_characters_you_want). var a = WikiTechy javascript' document.write(a.substr(4,8)); Techy ja tolowercase and touppercase-tolowercase() tolowercase and touppercase - tolowercase() puts the whole string in lower case, touppercase() puts the whole string in upper case. var b = 'WikiTechy javascript'; document.write(b.touppercase()) WIKITECHY JAVASCRIPT To convert the entire string into lower characters. var b = 'WikiTechy javascript'; document.write(b.tolowercase()) wikitechy javascript

6 Sample Code: JAVASCRIPT BASICS <!DOCTYPE html> <html> <body> <p>wikitechy - Javascript String Functions </p> <p id="wikitechy_text"></p> <script> var a = "WikiTechy"; var b = "Welcomes you for JavaScript Learning"; var c = a + b; </body> </html> document.getelementbyid("wikitechy_text").innerhtml = c; </script>

7 Code Explanation: JAVASCRIPT BASICS Paragraph tag displaying the text WikiTechy - Javascript String Functions Paragraph tag in which we are trying to get the result. The id of the paragraph tag is, WikiTechy_Text <p id="wikitechy_text"></p> Initialize the variables var a = "WikiTechy" and var b = "Welcomes you for JavaScript Learning" Addition operator is emphasized in the code var c = a + b Trying to fetch the element in the HTML WikiTechy_Text and accessing the inner HTML value and assign the variable c into it. Assign the variable c for the HTML element.

8 Sample Output:

9 Output: Displaying the text WikiTechy - Javascript Operators in the paragraph tag of the HTML page. Displaying the result of the variable with the operations(+)- concatenation performed on the variables.

Javascript Methods. concat Method (Array) concat Method (String) charat Method (String)

Javascript Methods. concat Method (Array) concat Method (String) charat Method (String) charat Method (String) The charat method returns a character value equal to the character at the specified index. The first character in a string is at index 0, the second is at index 1, and so forth.