RegExp.输入（$_）

Deprecated: This feature is no longer recommended. Though some browsers might still support it, it may have already been removed from the relevant web standards, may be in the process of being dropped, or may only be kept for compatibility purposes. Avoid using it, and update existing code if possible; see the compatibility table at the bottom of this page to guide your decision. Be aware that this feature may cease to work at any time.

注意：所有全局公开最后匹配状态的 RegExp 静态属性均已弃用。请参阅 已弃用的 RegExp 功能 了解更多信息。

¥Note: All RegExp static properties that expose the last match state globally are deprecated. See deprecated RegExp features for more information.

RegExp.input 静态访问器属性返回与正则表达式匹配的字符串。RegExp.$_ 是该属性的别名。

¥The RegExp.input static accessor property returns the string against which a regular expression is matched. RegExp.$_ is an alias for this property.

描述

¥Description

由于 input 是 RegExp 的静态属性，因此你始终将其用作 RegExp.input 或 RegExp.$_，而不是用作你创建的 RegExp 对象的属性。

¥Because input is a static property of RegExp, you always use it as RegExp.input or RegExp.$_, rather than as a property of a RegExp object you created.

每当 RegExp（但不是 RegExp 子类）实例成功匹配时，input 的值就会更新。如果没有匹配，则 input 为空字符串。你可以设置 input 的值，但这不会影响正则表达式的其他行为，并且在下一次成功匹配时该值将再次被覆盖。

¥The value of input updates whenever a RegExp (but not a RegExp subclass) instance makes a successful match. If no matches have been made, input is an empty string. You can set the value of input, but this does not affect other behaviors of the regex, and the value will be overwritten again when the next successful match is made.

示例

¥Examples

使用输入和 $_

¥Using input and $_

js
const re = /hi/g;
re.test("hi there!");
RegExp.input; // "hi there!"
re.test("foo"); // new test, non-matching
RegExp.$_; // "hi there!"
re.test("hi world!"); // new test, matching
RegExp.$_; // "hi world!"

规范

Specification
Legacy RegExp features
# additional-properties-of-the-regexp-constructor

¥Specifications

浏览器兼容性

BCD tables only load in the browser

¥Browser compatibility

也可以看看

¥See also