Javascript中为String对象添加??? Trim()??? 方法?????
<script??? language=Javascript>????
//自己动手为string添加Trim?????
function???
String.prototype.Trim()???
{return??? this.replace(/(^\s*)|(\s*$)/g,"");}????
function??? String.prototype.Ltrim()
{return??? this.replace(/(^\s*)/g,??? "");}?????
function??? String.prototype.Rtrim()
{return??? this.replace(/(\s*$)/g,??? "");}????? var??? str??? =??? "????? meizz????????? ";????? alert(str.Trim());????? </script>?



利用Javascript中每个对象(Object)的prototype属性我们可以为Javascript中的内置对象添加我们自己的方法和属性。
以下我们就用这个属性来为String对象添加三个方法：Trim,LTrim,RTrim(作用和VbScript中的同名函数一样)
String.prototype.Trim = function()
{
???? return this.replace(/(^\s*)|(\s*$)/g, "");
}
String.prototype.LTrim = function()
{
???? return this.replace(/(^\s*)/g, "");
}
String.prototype.Rtrim = function()
{
???? return this.replace(/(\s*$)/g, "");
}
怎么样，简单吧，下面看一个使用的实例：
<script language=javascript>
String.prototype.Trim = function()
{
???? return this.replace(/(^\s*)|(\s*$)/g, "");
}

var s = "???? leading and trailing spaces???? ";

window.alert(s + " (" + s.length + ")");

s = s.Trim();

window.alert(s + " (" + s.length + ")");

</script>


<script language=Javascript>
String.prototype.Trim=function(){return this.replace(/(^\s*)|(\s*$)/g,"!");}
String.prototype.Ltrim = function(){return this.replace(/(^\s*)/g, "!");}
String.prototype.Rtrim = function(){return this.replace(/(\s*$)/g, "!");}
var str = "????????? abc de ";
alert(str.Trim());
</script>

<script>
// 去左右空格
function Trim() {
return this.replace(/\s+$|^\s+/g,"");
}

// 去左空格
function LTrim() {
return this.replace(/^\s+/,"");
}

// 去右空格
function RTrim() {
return this.replace(/\s+$/,"");