String.prototype.search() - JavaScript 编辑

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

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

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

Using search()

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

Specifications

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

Browser compatibility

BCD tables only load in the browser

See also

• Using regular expressions in JavaScript
• String.prototype.match()
• RegExp.prototype.exec()