causing infinite loop in sharepoint OnpreRender

public partial class Login : FormsSignInPage
{
    protected override void OnInit(EventArgs e)
    {
        base.OnInit(e);
        bool testJS = IsJSEnabled;
        if (Request.QueryString[JSQRYPARAM] != null)
        {
            IsJSEnabled = Request.QueryString[JSQRYPARAM] == JSENABLED;
        }
    }

    protected override void OnPreRender(EventArgs e)
    {
        base.OnPreRender(e);
        if (IsJSEnabled)
        {
            string targeturl = GetAppendedUrl(JSQRYPARAM, JSDISABLED);
            HtmlGenericControl ctrl = new HtmlGenericControl("NOSCRIPT");
            ctrl.InnerHtml = string.Format("<meta http-equiv=REFRESH content=0;URL={0}>", targeturl);
            Page.Header.Controls.Add(ctrl);
        }
        else
        {
            if (!string.IsNullOrEmpty(NonJSTargetURL))
                Response.Redirect(NonJSTargetURL);
            HtmlGenericControl ctrl = new HtmlGenericControl("NOSCRIPT");
            ctrl.InnerHtml = string.Empty;
            Page.Header.Controls.Add(ctrl);
        }
    }