Email Validation for Text Box

Validate text box ,if enter string is email charecter or not

Aspx page

<asp:TextBox ID="txtEmail" runat="server" onClientClick="validateEmail()"/>

<script>

  Function validateEmail()
 {
     var reg=/^([A-ZaZo-9_\-\+\@([A-Za-Zo-9_\-\.])+\.([A-Za-Z]{2,4})$1;
     var mail=document.getElementById("txtEmai").value;
     if(reg.test(mail)==false)
     {
        alert('Invalid Email Address');
        return false;
 
     }
     return true
}


</script>

The above code is used to validate email Format

Thanks

Sreejesh