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。复制代码 代码如下:<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>