javascript中prototype步骤修改

javascript中prototype方法修改
今天做页面时发现了一个方法replace在匹配字符串时

<SCRIPT LANGUAGE="JavaScript">String.prototype.replaceAll = function(arg1,arg2){return this.replace(new RegExp(arg1,"g"),arg2);}var str = "asdfsd;asdfasdf;asdfasdfas";alert(str.replaceAll("\;","\|"));</SCRIPT>