JQuery is a javascript framework.
If you want pure js use this function on textbox onkeypress event:
<code>function CheckNumeric (e)
{
var key;
key = e.which ? e.which : e.keyCode;
if((key>=48 && key<=57)) {
e.returnValue= true;
}
else
{
alert("please enter Numeric only");
e.returnValue = false;
}
}</code>