RegExp()

Syntax



var variable = new RegExp(pattern, flags)

The RegExp() object represents a regular expression that is used for pattern matching.

The creation of the object takes pattern and flags parameters.

The pattern is a valid regular expression. The flags are either or both g (global) and i (ignore case).

Properties and Methods of the RegExp() Object

Property/Method	Description
RegExp.$*	Represents multiline
RegExp.$&	Represents lastmatch
RegExp.$_	Represents input
RegExp.$`	Represents leftContext
RegExp.$'	Represents rightContext
RegExp.$+	Represents lastParen
RegExp.$1,$2,...$9	Represents substring of matches
compile()	Compiles a regular expression
exec()	Executes the search for a match in a specified string
global	_Specifies whether to check the expressions against all possible matches
ignoreCase	Whether case is ignored or not during a string search
input	String that is matched
lastIndex	_Specifies the index at which to start matching the next string.
lastMatch	Last matched characters
lastParen	The last parenthesized substring match
leftContext	The substring preceding the most recent match
multiline	Specifies whether to search on multiple lines
rightContext	The substring following the most recent match
source	The string pattern
test()	Tests for a string match



<html>
    <body>
    <script language="JavaScript">
    <!--
    function isSSN(str){
       // xxx-xx-xxxx
       var regexp = /^(d{9}|d{3}-d{2}-d{4})$/;
       return regexp.test(str);
    }
    function checkInput(){
      var valid = true;
      var ssn = document.form1.ssn.value;
      if (!isSSN (ssn)){
          window.alert("Invalid SSN: " + ssn);
          valid = false;
      }
      else{
        alert(ssn + " is a valid SSN");
      }
    }
    -->
    </script>
    <form name="form1">
    Enter your SSN:
    <input type="text" size="15" name="ssn">
    <br><br>
    <input type="button" value="Validate SSN" onClick='checkInput()'>
    <br>
    </form>
    </body>
    </html>

RegExp() : RegExp Object : Regular Expressions JAVASCRIPT TUTORIALS

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