js替换字符串中所有指定的字符(实现代码)

第一次发现JavaScript中replace() 方法如果直接用str.replace("-","!") 只会替换第一个匹配的字符.

而str.replace(//-/g,"!")则可以全部替换掉匹配的字符(g为全局标志)。

replace()

The replace() method returns the string that results when you replace text matching its first argument

(a regular expression) with the text of the second argument (a string).

If the g (global) flag is not set in the regular expression declaration, this method replaces only the first

occurrence of the pattern. For example,

var s = "Hello. Regexps are fun." ;s = s.replace(//./, "!" ); // replace first period with an exclamation pointalert(s);

produces the string “Hello! Regexps are fun.” Including the g flag will cause the interpreter to

perform a global replace, finding and replacing every matching substring. For example,

var s = "Hello. Regexps are fun." ;s = s.replace(//./g, "!" ); // replace all periods with exclamation pointsalert(s);

yields this result: “Hello! Regexps are fun!”

所以可以用以下几种方式：

string.replace(/reallyDo/g, replaceWith);

string.replace(new RegExp(reallyDo, 'g'), replaceWith);

string：字符串表达式包含要替代的子字符串。

reallyDo：被搜索的子字符串。

replaceWith：用于替换的子字符串。

Js代码

<script type="text/javascript"> String.prototype.replaceAll = function(reallyDo, replaceWith, ignoreCase) {   if (!RegExp.prototype.isPrototypeOf(reallyDo)) {     return this.replace(new RegExp(reallyDo, (ignoreCase ? "gi": "g")), replaceWith);   } else {     return this.replace(reallyDo, replaceWith);   } } </script> 

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