在此页

• 句法
• 描述
• 范例
• 规范
• 浏览器兼容性
• 另请参阅
• 相关话题

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

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.

句法

regexObj.test(str)
					

参数

str

The string against which to match the regular expression.

返回

true if there is a match between the regular expression and the string str . Otherwise, false .

描述

使用 test() whenever you want to know whether a pattern is found in a string. test() returns a boolean, unlike the String.prototype.search() method (which returns the index of a match, or -1 if not found).

To get more information (but with slower execution), use the exec() method. (This is 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.

范例

Using test()

Simple example that tests if "hello" is contained at the very beginning of a string, returning a boolean result.

const str = 'hello world!';
const result = /^hello/.test(str);
console.log(result); // true
					

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

function testInput(re, str) {
  let midstring;
  if (re.test(str)) {
    midstring = 'contains';
  } else {
    midstring = 'does not contain';
  }
  console.log(`${str} ${midstring} ${re.source}`);
}
					

Using test() on a regex with the "global" flag

When a regex has the global flag set, test() will advance the lastIndex of the regex. ( RegExp.prototype.exec() also advances the lastIndex property.)

Further calls to test( str ) will resume searching str starting from lastIndex 。 lastIndex property will continue to increase each time test() 返回 true .

注意： As long as test() 返回 true , lastIndex will not reset—even when testing a different string!

When test() 返回 false , the calling regex's lastIndex property will reset to 0 .

The following example demonstrates this behaviour:

const regex = /foo/g; // the "global" flag is set
// regex.lastIndex is at 0
regex.test('foo')     // true
// regex.lastIndex is now at 3
regex.test('foo')     // false
// regex.lastIndex is at 0
regex.test('barfoo')  // true
// regex.lastIndex is at 6
regex.test('foobar')  //false
// regex.lastIndex is at 0
// (...and so on)
					

规范

规范
ECMAScript (ECMA-262) The definition of 'RegExp.test' in that specification.

浏览器兼容性

The compatibility table on 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. 更新 GitHub 上的兼容性数据

	Desktop						Mobile						Server
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet	Node.js
test	Chrome 1	Edge 12	Firefox 1	IE 4	Opera 5	Safari 1	WebView Android 1	Chrome Android 18	Firefox Android 4	Opera Android 10.1	Safari iOS 1	Samsung Internet Android 1.0	nodejs Yes

图例

完整支持

完整支持

另请参阅

• 正则表达式 chapter in the JavaScript 指南
• RegExp
• RegExp.prototype

元数据

• 最后修改： Aug 6, 2020

相关话题

1. 标准内置对象
2. RegExp
3. 特性
   1. RegExp.$1-$9
   2. RegExp.input ($_)
   3. RegExp.lastMatch ($&)
   4. RegExp.lastParen ($+)
   5. RegExp.leftContext ($`)
   6. RegExp.prototype.dotAll
   7. RegExp.prototype.flags
   8. RegExp.prototype.global
   9. RegExp.prototype.ignoreCase
   10. RegExp.prototype.multiline
   11. RegExp.prototype.source
   12. RegExp.prototype.sticky
   13. RegExp.prototype.unicode
   14. RegExp.rightContext ($')
   15. RegExpInstance.lastIndex
   16. get RegExp[@@species]
4. 方法
   1. RegExp.prototype.compile()
   2. RegExp.prototype.exec()
   3. RegExp.prototype.test()
   4. RegExp.prototype.toSource()
   5. RegExp.prototype.toString()
   6. RegExp.prototype[@@matchAll]()
   7. RegExp.prototype[@@match]()
   8. RegExp.prototype[@@replace]()
   9. RegExp.prototype[@@search]()
   10. RegExp.prototype[@@split]()
5. 继承：
6. Function
7. 特性
   1. Function.arguments
   2. Function.caller
   3. Function.displayName
   4. Function.length
   5. Function.name
8. 方法
   1. Function.prototype.apply()
   2. Function.prototype.bind()
   3. Function.prototype.call()
   4. Function.prototype.toSource()
   5. Function.prototype.toString()
9. Object
10. 特性
    1. Object.prototype.__proto__
    2. Object.prototype.constructor
11. 方法
    1. Object.prototype.__defineGetter__()
    2. Object.prototype.__defineSetter__()
    3. Object.prototype.__lookupGetter__()
    4. Object.prototype.__lookupSetter__()
    5. Object.prototype.hasOwnProperty()
    6. Object.prototype.isPrototypeOf()
    7. Object.prototype.propertyIsEnumerable()
    8. Object.prototype.toLocaleString()
    9. Object.prototype.toSource()
    10. Object.prototype.toString()
    11. Object.prototype.valueOf()
    12. Object.setPrototypeOf()