Email validation using javascript

function EmailValidate() {

var reg = /^([A-Za-z0-9_\-\.])+\@([A-Za-z0-9_\-\.])+\.([A-Za-z]{2,4})$/;
var address = document.getElementById("txtEmail").value;
if (reg.test(address) == false) {

alert('Invalid Email Address');
return false;
}
}


asp:TextBox ID="txtEmail" runat="server">

asp:Button ID="Button1" runat="server" Text="Validate" OnClientClick="return Validate();"