How to show a message box in an ASP.NET page?

Question

As I was a Windows programmer it was so easy to show a message box on a form.

But on an ASP.NET page I don\'t know how can I show it?

Actually I have some co

Answer 1

.aspx markup

Code-behind

protected void Page_Load(object sender, EventArgs e)
{
    if (HiddenField1.Value == "true")
    {

    }
    else
    {

    }
}