search() 方法执行正则表达式和 String 对象之间的一个搜索匹配。

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.

语法

str.search(regexp)

参数

regexp

一个正则表达式（regular expression）对象。如果传入一个非正则表达式对象 obj，则会使用 new RegExp(obj) 隐式地将其转换为正则表达式对象。

返回值

如果匹配成功，则 search() 返回正则表达式在字符串中首次匹配项的索引;否则，返回 -1。

描述

当你想要知道字符串中是否存在某个模式（pattern）时可使用 search()，类似于正则表达式的 test() 方法。当要了解更多匹配信息时，可使用 match()（但会更慢一些），该方法类似于正则表达式的 exec() 方法。

示例

例子：使用 search()

The following example searches a string with 2 different regex objects to show a successful search (positive value) vs. an unsuccessful search (-1)

var str = "hey JudE";
var re = /[A-Z]/g;
var 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

规范

浏览器兼容性

The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.

Gecko 注意事项

• 在 Gecko 8.0 及之前的版本，search() 的实现有问题：在调用该方法时，若不传递参数或者参数为 undefined，该方法将不会匹配空字符串，而是匹配字符串 "undefined"。这个问题已被修复，现在，"a".search() 和 "a".search(undefined) 都能正确返回 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).

参见

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