I have an issue with an internally-deployed intranet site (so no links, sorry), and Internet Explorer 9.
The site is a Rails 3 app, using HTML 5, with nothing out of the ordinary - no javascript, just html and CSS. The HTML successfully validates (using the W3C validator).
The users on site all have either Internet Explorer 8 on Windows XP or Internet Explorer 9 on Windows 7. Users with IE8 are able to use the site as expected, as am I using Chrome.
Users who have IE9 though are able to view pages, but if they try and submit a form, IE loads a blank page, where the source code contains only html, head and body tags. They then find that they can't view any page on the intranet, and the IE back button doesn't work. If I use tcpdump on the intranet server, I can see that when the user clicks submit, no data is sent over the wire from the client, so I can only assume that the blank page (and its source code) is generated by IE.
I have ensured that IE detects the site as being in the "Intranet Zone", and that that zone has the default security setting of Medium-Low. I have tried with Compatibility Mode on (the default for intranet sites) and with it off.
To make matters worse, the behaviour is inconsistent - the form is successfully submitted about 5% of the time, and the rest of the time we have the above result.
I feel like I'm missing something fundamental - what am I missing?
Compatibility Mode can actually be controlled by the server, and this would override the setting on the client. You should check if there is an html in the source for:
If so, you may want to test that with content="IE-edge", or at least verify that it has been tested in the mode that you think it should be using. I would also test it in the Low security zone.
Defining Document Compatibility
http://msdn.microsoft.com/en-us/library/cc288325%28v=vs.85%29.aspx#SetMode
Depending on what web server you are using, you should also check the server logs for errors when one if the IE9 browsers are trying to submit data.
Can you successfully submit if you go into the developer tools (F12) and change browser mode and document mode to different browser types?