Google Toolbar, IE9, and 404 status on NTFD page

[netblazon]

A client contacted me about a problem when going to a product page for a product that has been deleted. Only part of the content is being delivered - so you see part of the footer and some code. Sometimes it returns more code, sometimes less. I've tracked this down to being an issue only when the following is true:

1. Google Toolbar is installed
2. Browser is IE9 (does not happen in Firefox or Chrome; I can't test other versions of IE with the Google toolbar)
3. The page returns a 404 error code
4. The page is generated by Miva Merchant

I came to these conclusions by testing a broken product page which always returns a 404 error and shows the problem, against calling the NTFD template directly (http://www.domain.com/mm5/merchant.mvc?screen=NTFD), and for the latter, keeping the default 404 response code in the http-header item, and again testing it without it. The partial page load only happens with the direct NTFD url when the 404 code is returned.

I checked random, non-existent urls on some other Miva Merchant sites, and the same thing happens - partial page load.

I also checked some random, non-existent urls on some other NON-Miva sites, and the problem doesn't happen.

I'm at a lost for how to track this further. Has anyone else noticed, or even better, fixed this?

Thanks,
Susan

[Brandon MUS]

Re: Google Toolbar, IE9, and 404 status on NTFD page

I would look for some invalid HTML code on those troublesome pages. Typically that's the culprit when you have stuff not showing up in IE, but does in other browsers. The Google Toolbar shouldn't cause the issues as I don't believe it modifies the pages (other than prefilling forms sometimes).

That's where I would start.

[burch]

Re: Google Toolbar, IE9, and 404 status on NTFD page

With some work, we were able to recreate this in our test environment as long as the following conditions are met:

1. IE9 w/Google Toolbar
2. Google Toolbar's "Provide suggestions on navigation errors" setting enabled (the default on a new install as of today)
3. The page must output whitespace (or any other non-html content) before the doctype or html tags
4. There must be a transmission delay between the whitespace and start of the content. In our testing it took between 3.5-5 seconds to trigger the issue.

The provide suggestions on navigation errors setting claims to work basically the same way IE's 404 page replacement does. If the 404 page content is 512 bytes or less, it is replaced with a "helpful" page. I believe what is happening is that when there is a significant delay between the start of a response (the HTTP response headers being output) and the beginning of the HTML content, Google Toolbar thinks it has a short 404 page and displays its "suggestion". However, in our testing, when it does this any content that had been output before it gave up is still visible, and I think if the data it did receive contains CSS styles or partial html tags then the google "suggestions" will not always be visible.

Susan, on the sites you asked me to look at, all of the NTFD pages meet the criteria above. They all have whitespace before the start of the page content and a significant delay between the whitespace starting to be output and the actual content being output.

I would hunt down the source of the start-of-page whitespace, but more importantly you need to look for modules that are calling miva_output_flush(), because that is what causes the delay during transmission. Normally, as long as the page content is under 1MB (the case for the sites we looked at), Miva will buffer it until the page finishes loading and all of the content will be written at once. Additionally, if miva_output_flush() is called, Miva is unable to provide a Content-Length header, which may be a factor in Google Toolbar's behavior.

[netblazon]

Re: Google Toolbar, IE9, and 404 status on NTFD page

Brandon, thanks for the reply - but it definitely only happens when the toolbar is enabled.

Jon, thanks for your research and findings on the issue. I will try to see if I can figure out that issue based on your suggestions. However, with the client who originally reported the problem, when I looked at the response headers, there WAS a content-length one. But this definitely gives me somewhere to start. I'll let you know what I find.

[wajake41]

Re: Google Toolbar, IE9, and 404 status on NTFD page

Susan did you find a solution for this? Just ran into it on two of our sites. Any help/ideas would be appreciated.
Thanks, Larry

[netblazon]

Re: Google Toolbar, IE9, and 404 status on NTFD page

Only to try and remove all whitespace before the doctype. I don't think there's really any way for Miva to fix this as it's a client-side (browser/plug-in) bug.

[JFancett]

Re: Google Toolbar, IE9, and 404 status on NTFD page

Not sure if it's related but in our ColdFusion apps we used to do a lot of the SQL data processing before the HTML tag. Starting with our switch to HTML5 from XHTML transitional, putting anything before the HTML doctype breaks the layout in IE so we've been forced to move it inside that tag and before the head tag.

[wajake41]

Re: Google Toolbar, IE9, and 404 status on NTFD page

Tried modifying our NTFD page. Unable to resolve the IE problem. Just live with it I suppose.
Larry

[nottheusual1]

Re: Google Toolbar, IE9, and 404 status on NTFD page

Has anyone tried having the NTFD page render an alternative page (by using toolkit, eg) if IE is the browser? Same principle as detecting a mobile browser, maybe?