Validate only numeric on key press ASP.Net

Here are the script to validate only numeric on key press.Write below code in tag

function isNumberKey(evt)
    {
   var charCode = (evt.which) ? evt.which : event.keyCode
   if (charCode > 31 && (charCode < 48 || charCode > 57))
      return false;

   return true;
    }



Write below code on TextBox control to validate only numeric value


onkeypress="return isNumberKey(event);"