String.prototype.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 regexp is passed, it is implicitly converted to a RegExp with new RegExp(regexp).

Return value

The index of the first match between the regular expression and the given string, or -1 if no match was found.

Description

When you want to know whether a pattern is found, and also know its index within a string, use search(). (If you only want to know if it exists, use the similar test() method on the RegExp prototype, which returns a boolean.) 

For more information (but slower execution) use match() (similar to the regular expression exec() method).

Examples

The following example searches a string with two different regex objects to show a successful search (positive value) vs. an unsuccessful search (-1)

let str = "hey JudE"
let re = /[A-Z]/g
let re2 = /[.]/g
console.log(str.search(re))   // returns 4, which is the index of the first capital letter "J"
console.log(str.search(re2))  // returns -1 cannot find '.' dot punctuation

Specifications

Specification
ECMAScript Latest Draft (ECMA-262)
The definition of 'String.prototype.search' in that specification.

Browser compatibility

Update compatibility data on GitHub
DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
searchChrome Full support 1Edge Full support 12Firefox Full support 1IE Full support 4Opera Full support YesSafari Full support 1WebView Android Full support 1Chrome Android Full support 18Firefox Android Full support 4Opera Android Full support YesSafari iOS Full support 1Samsung Internet Android Full support 1.0nodejs Full support Yes
flags
DeprecatedNon-standard
Chrome No support NoEdge No support NoFirefox No support 1 — 49IE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android No support 4 — 49Opera Android No support NoSafari iOS No support NoSamsung Internet Android No support Nonodejs No support No

Legend

Full support  
Full support
No support  
No support
Non-standard. Expect poor cross-browser support.
Non-standard. Expect poor cross-browser support.
Deprecated. Not for use in new websites.
Deprecated. Not for use in new websites.

Gecko-specific notes

  • flags was a non standard second argument only available in Gecko : str.search(regexp, flags)
  • 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