The use method of JS Trim,ltrim,rtrim function

Today to use JavaScript to remove a text box at the ends of the string space, began to think there is a Trim,ltrim,rtrim function (ASP has these three functions, confused), the results find half a day, did not find. Finally, we find a custom function that uses the same functionality as the regular implementation.
<script type= "Text/javascript" >
function Trim (str) {//Remove spaces at left and right ends
Return Str.replace (/(^\s*) | ( \s*$)/g, "");
}
function LTrim (str) {//delete left space
Return Str.replace (/(^\s*)/g, "");
}
function RTrim (str) {//Remove the right space
Return Str.replace (/(\s*$)/g, "");
}
</script>
How to use
<script>
function aaa ()
{
var S=document.getelementbyid ("text box ID"). value;
Alert (Trim (s));
}
</script>