string.search

The search() method executes a search for a match between a regular expression and this String object.

Syntax

str.search(regexp)

Parameters

regexp

A regular expression object. If a non-RegExp object obj is passed, it is implicitly converted to a RegExp by using new RegExp(obj).

Return value

The index of the first match between the regular expression and the given string; if not found, -1.

Description

When you want to know whether a pattern is found and also its index in a string use search() (if you only want to know it exists, use the similar test() method, which returns a boolean); for more information (but slower execution) use match() (similar to the regular expression exec() method).

Examples

Using search()

The following example logs a message which depends on the success of the test.

function testinput(re, str) {
  var midstring;
  if (str.search(re) != -1) {
    midstring = ' contains ';
  } else {
    midstring = ' does not contain ';
  }
  console.log(str + midstring + re);
}

Specifications

Specification	Status	Comment
ECMAScript 3rd Edition (ECMA-262)	Standard	Initial definition. Implemented in JavaScript 1.2.
ECMAScript 5.1 (ECMA-262) The definition of 'String.prototype.search' in that specification.	Standard
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'String.prototype.search' in that specification.	Standard
ECMAScript 2017 Draft (ECMA-262) The definition of 'String.prototype.search' in that specification.	Draft

Browser compatibility

Gecko-specific notes

• Prior to Gecko 8.0, search() was implemented incorrectly; when it was called with no parameters or with undefined, it would match against the string 'undefined', instead of matching against the empty string. This is fixed; now 'a'.search() and 'a'.search(undefined) correctly return 0.
• Starting with Gecko 39 (Firefox 39 / Thunderbird 39 / SeaMonkey 2.36), the non-standard flags argument is deprecated and throws a console warning (bug 1142351).
• Starting with Gecko 47 (Firefox 47 / Thunderbird 47 / SeaMonkey 2.44), the non-standard flags argument is no longer supported in non-release builds and will soon be removed entirely (bug 1245801).
• Starting with Gecko 49 (Firefox 49 / Thunderbird 49 / SeaMonkey 2.46), the non-standard flags argument is no longer supported (bug 1108382).

See also

• String.prototype.match()
• RegExp.prototype.exec()