How can I prevent Telerik RadChart from generating an onerror attribute?

Question

We're using the Telerik Rad Controls for ASP.Net Ajax on an ASP.Net MVC project. The RadChart generates the following HTML:

<img onerror="if(confirm('Error loading RadChart image.\nYou may also wish to check the ASP.NET Trace for further details.\nDisplay stack trace?'))window.location.href=this.src;" src="ChartImage.axd?UseSession=true&amp;ChartID=e25ad666-e05b-4a92-ac0c-4f2c729b9382_chart_ctl00$MainContent$AverageCTMChart&amp;imageFormat=Png&amp;random=0.501658702968461" usemap="#imctl00_MainContent_AverageCTMChart" style="border-width: 0px;" alt="">

I'd like to remove the onerror attribute; I don't really want the customers being offered the option to see a stack trace if something goes wrong. I can't see any way to control the markup that this control generates. Google searches provide no help. Has anyone dealt with this before?

How do I remove the onerror attribute?

Answer 1

You could do something like this, just add it to the bottom of the page or call removeOnError in a load event somewhere.

function removeOnError(){
    //Grab all images
    var imgs = document.getElementsByTagName('img');
    for(var i=0;i<imgs.length;i++){
        //If they've got the onerror attribute
        if(imgs[i].onerror){
            //set it to null
            imgs[i].onerror = null;
        }
    }
}
//Call the function above
removeOnError();

Edit

Looking at Telerik's site it doesn't appear to be an option so the only way that I can think of is to override the Render event for your page and manually rip it out:

protected override void Render(HtmlTextWriter writer)
{
    using (System.IO.MemoryStream MS = new System.IO.MemoryStream())
    {
        using (System.IO.StreamWriter SW = new System.IO.StreamWriter(MS))
        {
            HtmlTextWriter NW = new HtmlTextWriter(SW);
            base.Render(NW);
            NW.Flush();
            MS.Position = 0;
            using (System.IO.StreamReader SR = new System.IO.StreamReader(MS))
            {
                string html = SR.ReadToEnd();
                MatchCollection MC = Regex.Matches(html, "<img.*?(?<OnError>onerror=\".*?\").*?>");
                foreach (Match M in MC)
                {
                    if (M.Success)
                    {
                        html = html.Replace(M.Groups["OnError"].Value, "");
                    }
                }
                Response.Write(html);
                SR.Close();
            }
        }
    }
} 

Answer 2

Guys,

The onerror only ever shows in debug configuration. Once you deploy your app in Release the attribute does not get rendered!