Client Side Web Development

Re: onbeforeunload and eval Problems in IE

Scott Mitchell — Thu, 14 Apr 2005 15:39:49 GMT

For those who are interested, the workaround provided by Telerik was to put the eval() function in a try...catch block, which would have the effect of suppressing the error message shown in IE. It does serve as a workaround, although seems like a bit of a hack. Stupid IE.

Re: onbeforeunload and eval Problems in IE

BasicDatePicker — Wed, 13 Apr 2005 21:03:24 GMT

Hi Scott,

We tried to come up with a solution, although nothing worked. dang.

We did find that removing the eval() still produced the error. We're going to sleep on this and see what happens. If you come up with a solution or any other notes/comments, please post a follow-up.

onbeforeunload and eval Problems in IE

Scott Mitchell — Tue, 12 Apr 2005 20:40:02 GMT

I am using the onbeforeunload client-side event to prompt a user when leaving a page after they have made changes, as discussed in this article of mine: Using ASP.NET to Prompt a User to Save When Leaving a Page. The problem I am having is with the page unloading via eval. Specifically, I am using telerik r.a.d. menu, which redirects users to another page via script like:

eval('window.location.href='url of menu item');

When a user attempts to leave the page via a menu option, they get the prompt, as expected, but if they click Cancel there is a script error: Unspecified error on the line number of the eval() function call. This works just fine in Firefox.

I created a VERY simple page to test this out and confirm that it is the eval() function. The page below, when visited through IE, displays the prompt and if I click Cancel I get the same Unspecified error.

<script>
function foo()
{
return "bar";
}

window.onbeforeunload = foo;

eval('window.location.href=\'http://www.google.com\'');
</script>

I was unable to find any info via Google as to if this is a well-known bug or if there are any workarounds. Any ideas/suggestions/comments most appreciated. (I'm posting this in the telerik forums as well; hopefully there's an easy way to get rid of those eval() statements, but I doubt it... )

TIA