Question

I am trying to show exception message through javascript alert box.

Here is the sample code.

public static void HandleException(Page page, Exception ex)
{
    string message = ex.Message.ToString();
    ScriptManager.RegisterClientScriptBlock(page, page.GetType(), "", "alert('"+message+"');", true);

}

It runs if i give literal values for the string variable.
e.g.

string message = "Hello World";

But it fails if I give message = ex.Message;

Any Idea?

Answer 1

You need to encode it, for example using JavaScriptSerializer because if the message contains some escape characters like ' or " this will definitely break your javascript:

var message = new JavaScriptSerializer().Serialize(ex.Message.ToString());
var script = string.Format("alert({0});", message);
ScriptManager.RegisterClientScriptBlock(page, page.GetType(), "", script, true);