Allow only alphanumeric in textbox using javascript and regular expression

function validate(evt) {
     var theEvent = evt || window.event;
     var key = theEvent.keyCode || theEvent.which;
     key = String.fromCharCode(key);
     var regex = /^[0-9a-zA-Z\s\b]+$/;
     if (!regex.test(key)) {
         theEvent.returnValue = false;
         if (theEvent.preventDefault) 
             theEvent.preventDefault();
      }
 }

<asp:TextBox ID="txtVal" runat="server" onKeyPress="validate(e);"></asp:TextBox>

var re = /^-?\d+$/;
var matches = re.test(args.Value);

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

        return true;
 }