js实现TRIM去除空格功能

<SCRIPT LANGUAGE="JavaScript">
<!--
//出处:网上搜集
// Trim() , Ltrim() , RTrim()

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, "");
}

//-->

//1去除字符串前后所有空格
function Trim(str){  
        return str.replace(/(^\s*)|(\s*$)/g, "");  
}  
//2去除字符串中所有空格(包括中间空格,需要设置第2个参数为:g)
function Trim(str,is_global)
{
var result;
result = str.replace(/(^\s+)|(\s+$)/g,"");
if(is_global.toLowerCase()=="g")
    result = result.replace(/\s/g,"");
return result;
}  
</SCRIPT>

<input type="text" value="   前后都是空格    " id="space">
<input type="button" value="去前后空格" onclick="javascript:document.getElementById('space').value=document.getElementById('space').value.Trim();document.getElementById('space').select();">
<input type="button" value="去前空格" onclick="javascript:document.getElementById('space').value=document.getElementById('space').value.LTrim();document.getElementById('space').select();">
<input type="button" value="去后空格" onclick="javascript:document.getElementById('space').value=document.getElementById('space').value.RTrim();document.getElementById('space').select();">
<input type="button" value="还原" onclick="javascript:document.getElementById('space').value='     前后都是空格    ';">