12 replies to this topic

[BrianR]

My web designer and I recently finished a small site and all was well with the world. Then the client reported a very intermittent fault.

When any page of the site is displayed, the text (which is in a table) loads first and then a largish surrounding graphic drops into place around the text. Very rarely, the arrival of the graphic on the screen causes the entire text table to repeat vertically over and over again at about 3mm intervals.

So far, it has only happened on three of the clients own pc's - he has an adsl (broadband) line which is distributed to 12ish pc's via a router.

Several people have tried to replicate the fault many times on different pc's that are not on the client's site, but without success. So it would seem that the fault somehow lies with the client's system, but he's not convinced!

We've checked the code over and over, but we're now reduced to a lot of head-scratching.

So can anyone give me any idea of what we're missing here?? - my sanity's at stake!

BrianR

[qwerty]

Has it happened on the same browser every time (including version number)?

And, (this may matter depending on the answer to the first question) are there any nested tables on the page, or just the one you mentioned?

[compar]

What browser is the client using? This sound like the kind of thing that will happen in Netscape to sites designed and tested solely in IE.

Could his firewall be getting in the way? What are you loading besides a table and a graphic?

Have you run the code through any of the several HTML verifiers that are available?

Just some thoughts.

[BrianR]

Bob & Bob

They are using IE5 and above and I believe that there is only one table per page.

I'm not sure whether the designer verified the html or not - I'll check.

Meanwhile, I've PM'd the site address to you both - perhaps that will help.

Thanks for your input.

BrianR

[chrishirst]

When I was a corporate wage slave (IT Manager), I've seen a similar thing happen, but only when you scroll up the page, The page will load ok but then break up into horizontal lines as you scrolled, only ever happened on certain machines and certain sites. zdnet.co.uk was one I seem to remember.
After a bit of experimenting with the lab rat machines the only common factor seened to be the video card on the affected machines. This was on about 6 PCs out 100+ swapped the video cards to ATI from S3 and it went away (or nobody bothered to complain anymore)


Chris.

[polarmate]

It could be the graphics display card. I had a non-standard graphics card on my older machine and it would display entire pages with missing lines - just white space instead of text. Scrolling up and down would make tables overlap onto one another. Minimizing and maximizing the page usually helped get the display back or simply 'Select All' or Ctrl+A. In my case, it was definitely the graphics card and not the browser/version or the Internet connection

[compar]

Bob & Bob

They are using IE5 and above and I believe that there is only one table per page.

I'm not sure whether the designer verified the html or not - I'll check.

Meanwhile, I've PM'd the site address to you both - perhaps that will help.

Sorry for being so slow getting back to you. I loaded the page in both Netscape 7.1 and IE 6 and it displayed perfectly.

The graphic does take some time to load even on my high speed connection. Have you tried to optimize the graphic -- reduce the number of colours in the palette? Please note the English/Canadain spelling of colour just for you.

[Searchaware]

I have seen the behaviour described from time to time on various sites I have worked on over the years. After testing I came to the conclusion that it was likely to be a local hardware issue as polarmate and chrishirst indicated.

You can sometimes get oddities when you mix certain versions of Windows with certain builds of IE or Netscape which can cause problems but I would think it more likely to be to do with the display adapter.

BrianR if you want me to cast an eye over the code feel free to PM me although I don't expect I will come up with anything that the other guys haven't spotted...

Simon

[BrianR]

Thank you very much for your input, guys - particularly about the graphics card possibly being the root cause of the problem - I'd not thought of that!

BrianR

[Ron Carnell]

It's always hard to track down problems that can't be easily reproduced. The site is on a fairly standard Apache 1.3.27 server. FrontPage extensions loaded, mod_ssl, but certainly nothing unusual. In fact, it's pretty sparse.

I ran the Ultimate Web Page Test (patent pending). Otherwise known as Netscape 4.7, with both JavaScript and CSS disabled. Your page lost a little formatting, but very little, and actually came out much better than most modern pages would. Certainly, no sign of the problem you've described.

It may indeed be a hardware problem, but if so, the symptoms should be seen on other web pages, too. Some other pages, at least. I'm guessing it's a bug with the software driver for the video card, rather than the card itself. The only thing at all unusual about the page is the background graphic. That sucker is huge, and the browser is trying to tile it? I get tired just thinking about it.

You could try changing the video cards, or at least upgrading the video drivers. If it works, that would probably make the client happy because they would no longer see the problem. But if they have the problem, chances are there are going to be visitors out there without upgraded drivers. The real problem would persist.

If it was me, I would define the page background using CSS and setting it to no-repeat. If someone comes to the site without a CSS enabled browser, they obviously won't get the background image, but the site should otherwise be perfectly usable. And I'm pretty confident (or hopeful?) the problem will disappear if the tiling disappears.

[mcanerin]

My apologies for not getting here sooner, but it looks like my compatriots are heading in the right direction

I've tested the site on every machine in my lab and have been unable to replicate the problem. However, I can tell you that it used to happen to me on an old system of mine at random.

I can't remember what the video card was (it was either an ATI or an onboard SiS, but I can't remember more than that, sorry - I do remember it had low video ram, 2 or 4 MB)

The issue popped up randomly when I tried to scroll a complex page - it created the issue that you seem to be having.

You have used the size tags throughout the tables, which is a good thing, but it may still be too complex for the card to handle. I would also check to see if the client has had this happen on other sites or programs. It happened in Front Page text mode with me as well.

I once had a client who would phone us for our free tech support and tell us that our (high end oil field) program had stopped working. When we got there, it was obvious that ALL his programs had stopped working, since his machine had crashed. But since we were the free guys he called us

I don't know if it's the case here, but I always check for those scenarios now.

In order:

1. See if it happens on other sites or programs too - if so, it's probably the video card - either update the drivers and DirectX, or replace the cards. You could even temporarily install a good card on the machine and try to reproduce it.

2. If not (and you believe them), simplify the design of the pages by removing the tables and replacing with CSS or otherwise. Tables are hard on pages because they are designed to show relationships, not positions. Another issue may be the img rollovers, but I'm not inclined to believe it.

This is a nice, well designed site with no "weird" stuff. I'm really leaning towards hardware issues, especially in view of the difficulty we've been having reproducing it. The only thing we can't reproduce is the clients video drivers and hardware.

One last point, if it turns out to be your clients video card, you may run into him getting defensive and saying that you shouldn't be making sites that don't work on everything anyway. You may end up having to simply the site design regardless I'd go pure CSS. Frankly, it's not too complex to start with, so I'd put it at the end of the list.

Yours,

Ian

[BrianR]

Thank you Ron and Ian for your detailed and very helpful input.

Now that we're getting a consensus from my techie colleagues, I feel confident that we are getting to the bottom of this thorny problem. I shall progress matters with the client...

Thanks again.

BrianR

[air-dog]

Brian,

The HTML on the page is solid. The fault defiantly lies with the client's system and like most here mentioned, almost defiantly with the graphics card. I would do as Ron Carnell recommends

> define the page background using CSS and setting it to no-repeat.

Also compar mentioned

> the number of colours in the palette

Although the background is a jpg it will benefit from reducing it in some way that will ease up on the graphics card resources.