test Method (Regular Expression) (JavaScript)

Returns a Boolean value that indicates whether or not a pattern exists in a searched string.




Required. An instance of a Regular Expression object containing the regular expression pattern and applicable flags.

Required. The string on which to perform the search.


The test method checks to see if a pattern exists within a string and returns true if so, and false otherwise.

The properties of the global RegExp object are not modified by the test method.


The following example illustrates the use of the test method. To use this example, pass the function a regular expression pattern and a string. The function will test for the occurrence of the regular expression pattern in the string and return a string indicating the results of that search:

function TestDemo(re, teststring)  
   // Test string for existence of regular expression.  
   var found = re.test(teststring)  

   // Format the output.  
   var s = "";  
   s += "'" + teststring + "'"  

   if (found)  
      s += " contains ";  
      s += " does not contain ";  

   s += "'" + re.source + "'"  


Supported in the following document modes: Quirks, Internet Explorer 6 standards, Internet Explorer 7 standards, Internet Explorer 8 standards, Internet Explorer 9 standards, Internet Explorer 10 standards, Internet Explorer 11 standards. Also supported in Store apps (Windows 8 and Windows Phone 8.1). See Version Information.

Applies To: Regular Expression Object

See Also

RegExp Object
Regular Expression Object
Regular Expression Syntax (JavaScript)