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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/javascript/reference/global_objects/regexp/test | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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diff --git a/files/zh-cn/web/javascript/reference/global_objects/regexp/test/index.html b/files/zh-cn/web/javascript/reference/global_objects/regexp/test/index.html new file mode 100644 index 0000000000..d742f6c172 --- /dev/null +++ b/files/zh-cn/web/javascript/reference/global_objects/regexp/test/index.html @@ -0,0 +1,128 @@ +--- +title: RegExp.prototype.test() +slug: Web/JavaScript/Reference/Global_Objects/RegExp/test +tags: + - JavaScript + - Method + - Prototype + - RegExp + - Regular Expressions +translation_of: Web/JavaScript/Reference/Global_Objects/RegExp/test +--- +<div>{{JSRef}}</div> + +<p><code><strong>test()</strong></code> 方法执行一个检索,用来查看正则表达式与指定的字符串是否匹配。返回 <code>true</code> 或 <code>false</code>。</p> + +<div>{{EmbedInteractiveExample("pages/js/regexp-prototype-test.html", "taller")}}</div> + +<div class="hidden">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 <a href="https://github.com/mdn/interactive-examples">https://github.com/mdn/interactive-examples</a> and send us a pull request.</div> + +<h2 id="Syntax" name="Syntax">语法</h2> + +<pre class="notranslate"><var>regexObj</var>.test(str)</pre> + +<h3 id="Parameters" name="Parameters">参数</h3> + +<dl> + <dt><code>str</code></dt> + <dd>用来与正则表达式匹配的字符串</dd> +</dl> + +<h3 id="返回值">返回值</h3> + +<p>如果正则表达式与指定的字符串匹配 ,返回<code>true</code>;否则<code>false</code>。</p> + +<h2 id="Description" name="Description">描述</h2> + +<p>当你想要知道一个正则表达式是否与指定的字符串匹配时,就可以使用 <code>test()</code>(类似于<code> </code> {{jsxref("String.prototype.search()")}} 方法),差别在于test返回一个布尔值,而 search 返回索引(如果找到)或者-1(如果没找到);若想知道更多信息(然而执行比较慢),可使用{{jsxref("RegExp.prototype.exec()", "exec()")}} 方法(类似于 {{jsxref("String.prototype.match()")}} 方法)。 和 {{jsxref("RegExp.prototype.exec()", "exec()")}} (或者组合使用),一样,在相同的全局正则表达式实例上多次调用<code><code>test</code></code>将会越过之前的匹配。</p> + +<h2 id="Examples" name="Examples">示例</h2> + +<h3 id="Example_Using_test" name="Example:_Using_test">使用 <code>test()</code></h3> + +<p>一个简单的例子,测试 "hello" 是否包含在字符串的最开始,返回布尔值。</p> + +<pre class="brush: js notranslate">let str = 'hello world!'; +let result = /^hello/.test(str); +console.log(result); +// true +</pre> + +<p>下例打印一条信息,该信息内容取决于是否成功通过指定测试:</p> + +<pre class="brush: js notranslate">function testinput(re, str){ + var midstring; + if (re.test(str)) { + midstring = " contains "; + } else { + midstring = " does not contain "; + } + console.log(str + midstring + re.source); +} +</pre> + +<h3 id="当设置全局标志的正则使用test">当设置全局标志的正则使用<code>test()</code></h3> + +<p>如果正则表达式设置了全局标志,<code>test() </code>的执行会改变正则表达式 <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/lastIndex" title="The lastIndex is a read/write integer property of regular expression instances that specifies the index at which to start the next match."><code>lastIndex</code></a>属性。连续的执行<code>test()</code>方法,后续的执行将会从 lastIndex 处开始匹配字符串,({{jsxref("RegExp.prototype.exec()", "<code>exec()</code>")}} 同样改变正则本身的 <code><a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/lastIndex" title="The lastIndex is a read/write integer property of regular expression instances that specifies the index at which to start the next match.">lastIndex</a>属性值</code>).</p> + +<p>下面的实例表现了这种行为: </p> + +<pre class="brush: js notranslate">var regex = /foo/g; + +// regex.lastIndex is at 0 +regex.test('foo'); // true + +// regex.lastIndex is now at 3 +regex.test('foo'); // false +</pre> + +<h2 id="规范">规范</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">Specification</th> + <th scope="col">Status</th> + <th scope="col">Comment</th> + </tr> + <tr> + <td>{{SpecName('ES3')}}</td> + <td>{{Spec2('ES3')}}</td> + <td>Initial definition. Implemented in JavaScript 1.2.</td> + </tr> + <tr> + <td>{{SpecName('ES5.1', '#sec-15.10.6.3', 'RegExp.test')}}</td> + <td>{{Spec2('ES5.1')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('ES6', '#sec-regexp.prototype.test', 'RegExp.test')}}</td> + <td>{{Spec2('ES6')}}</td> + <td></td> + </tr> + <tr> + <td>{{SpecName('ESDraft', '#sec-regexp.prototype.test', 'RegExp.test')}}</td> + <td>{{Spec2('ESDraft')}}</td> + <td></td> + </tr> + </tbody> +</table> + +<h3 id="sect1"></h3> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + +<div class="hidden">这个页面的兼容性表格是由结构数据生成。如果你想对数据作出贡献,详情请前往 <a href="https://github.com/mdn/browser-compat-data">https://github.com/mdn/browser-compat-data</a> 并给我们一个PR。</div> + +<p>{{Compat("javascript.builtins.RegExp.test")}}</p> + +<h2 id="Firefox特殊注意">Firefox特殊注意</h2> + +<p>在 Firefox 8之前, <code>test()</code> 被不正确地实现了;当无参数地调用时,它会匹配之前的输入值 (RegExp.input 属性),而不是字符串"undefined"。这已经被修正了;现在 <code>/undefined/.test()</code> 正确地返回<code>true</code>,而不是错误。</p> + +<h2 id="相关链接">相关链接</h2> + +<ul> + <li>在<a href="/zh-CN/docs/Web/JavaScript/Guide" title="JavaScript/Guide">JavaScript指南</a>的<a href="/zh-CN/docs/Web/JavaScript/Guide/Regular_Expressions" title="JavaScript/Guide/Regular_Expressions">正则表达式</a>章节</li> + <li>{{jsxref("RegExp")}}</li> +</ul> |