2 IE8 behave differently

I am having a problem where 2 IE8 (with the same version number 8.0.6001.18702) behave differently in processing a webpage. The misbehaving one is of course used by the client :) , and I just cannot reproduce it on my machine or on our test machine. It is all good on Firefox btw.

How can I narrow down what is causing this problem?

Thanks

Edit: Clicking on a submit button o开发者_如何学Cbviously should submit a form, but on the client's IE, it just doesn't do that.

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Have you tested on other browsers than Firefox and IE? The default behavior of button and input buttons varies a bit from browser to browser (I think the standard used to be a bit vague about this or was easily misinterpreted).. What type of button is it? I think <input type="submit"> tends to be more reliable across browsers..

BTW, If you've attached some JavaScript to the button it may be that's what causing the problems, too... IE has a very small yellow warning icon on the status indicationg script errors, but since IE is "somewhat quirky" you'll get used to it being there all the time and you might not notice a fatal error ;)

(IE8 supposedly removed a lot of nonstandard quirks and got more "standard compliant", but in my experience they've allso created a lot of really weird new quirks, unseen in any previous version...)

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Check if there are differences with respect to add-ins (plugins), toolbars etc. E.g. Skype add-in inserts it's own formatting of phone numbers and a way to make a call by clicking on them.

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You could ask him to execute ie8 with the command line argument -extoff.
If it's not fixing the problem, the compatibility mode is maybe triggered somehow.
Of course remember to check that you are not calling local files (that's obvious but who knows).

update: (just read the comments) is js enabled on his side too?