validating textbox for allowing alphabetics and spl charecters like ,.+-! etc using javascript

<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title></title>
<script type="text/javascript">
function onlyAlphabets(event) {
var regex = new RegExp("^[A-Za-z\\s!+,.-]*$");
var key = String.fromCharCode(event.charCode ? event.which : event.charCode);
if (!regex.test(key)) {
event.preventDefault();
alert("eneter numbers");
return false;
}
}
</script>
</head>
<body>
<form runat="server">
<div align="center">
<asp:TextBox ID="TextBox1" runat="server" onkeypress="return onlyAlphabets(event);"></asp:TextBox>
</div>

</form>

</body>
</html>