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    RegExp.prototype.test()

    Summary

    The test() method executes a search for a match between a regular expression and a specified string. Returns true or false.

    Syntax

    regexObj.test(str)

    Parameters

    str
    The string against which to match the regular expression.

    Returns

    Boolean. true or false.

    Description

    Use test() whenever you want to know whether a pattern is found in a string (similar to the String.prototype.search() method); for more information (but slower execution) use the exec() method (similar to the String.prototype.match() method). As with exec() (or in combination with it), test() called multiple times on the same global regular expression instance will advance past the previous match.

    Examples

    Example: Using test()

    The following example prints a message which depends on the success of the test:

    function testinput(re, str){
      var midstring;
      if (re.test(str)) {
        midstring = ' contains ';
      } else {
        midstring = ' does not contain ';
      }
      console.log(str + midstring + re.source);
    }
    

    Specifications

    Specification Status Comment
    ECMAScript 3rd Edition. Standard Initial definition. Implemented in JavaScript 1.2.
    ECMAScript 5.1 (ECMA-262)
    The definition of 'RegExp.test' in that specification.
    Standard  
    ECMAScript 6 (ECMA-262)
    The definition of 'RegExp.test' in that specification.
    Draft  

    Browser compatibility

    Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
    Basic support (Yes) (Yes) (Yes) (Yes) (Yes)
    Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
    Basic support (Yes) (Yes) (Yes) (Yes) (Yes) (Yes)

    Gecko-specific notes

    Prior to Gecko 8.0 (Firefox 8.0 / Thunderbird 8.0 / SeaMonkey 2.5), test() was implemented incorrectly; when it was called with no parameters, it would match against the value of the previous input (RegExp.input property) instead of against the string "undefined". This is fixed; now /undefined/.test() correctly results in true, instead of an error.

    See also

    Document Tags and Contributors

    Last updated by: fscholz,