ASP.Net: Catch exception and display exception message, Source and StackTrace in JavaScript alert message box

Its a divide by 0 error.

protected void Page_Load(object sender, EventArgs e)
{
    try
    {
        int a = 0;
        int i = 3 / a;
    }
    catch (Exception b)
    {
        string message = string.Empty;
        message += b.StackTrace;
        message += b.InnerException;
        message += b.Source;
        message += b.Source;
        ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('" + message + "');", true);
    }
}