javascript怎样去掉字符串左右空格?

 
<SCRIPT LANGUAGE="JavaScript">
// 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, "");
}
 
</SCRIPT>
 
str = str.replace(/[ ]/g,""); //替换所有空格
str.replace(/(^\s*)|(\s*$)/g, ""); //去掉左右空格
str.replace(/(\s*$)/g, ""); //去掉右空格
str.replace(/(^\s*)/g, ""); //去掉左空格