Change TextBox Color on Validation Fail in Asp.net

This Blog Show how to change TextBox color when validation fails.

Follow this simple steps
1. write Following javascript code on  head tag

    function changeColor(source, args)
        {
     
            var txtuser = document.getElementById('<%= txtUserName.ClientID %>');
            if(args.Value.length == 0)
            {
                txtuser.style.border="red solid 1px";
                args.IsValid = false;
            }
            else
            {
                txtuser.style.background = 'white';
                args.IsValid = true;
            }
        }

2. Drag Textbox on Form give id="txtUserName"

<asp:TextBox ID="txtUserName" runat="server" ></asp:TextBox>

3. Drag CustomValidator control from toolbox.Set Following Properties

<asp:CustomValidator ID="CustomValidator1" runat="server"  ControlToValidate="txtUserName"
            ErrorMessage="" ValidateEmptyText="True"
            ClientValidationFunction="changeColor"></asp:CustomValidator>

4.Take one Button on form.

5. Run Website.