Should we force IE compatibility mode off?

[NickColley]

When testing some IE8 issues I accidentally turned on IE7 standards mode, I think when the page errors it'll prompt you to turn it on.

I'm wondering if we should include meta tags, that you often see people using?

https://msdn.microsoft.com/en-gb/en-en/library/cc817574.aspx

<meta http-equiv="X-UA-Compatible" content="IE=edge" /> 

[NickColley]

[36degrees]

Yep. I think that given IE8 is the lowest version of IE we support, it makes sense to do this 👍

[paulwaitehomeoffice]

I’m not sure the meta tag will entirely “force” compatibility mode off. I wrote up the compatibility mode settings in IE 8 some time ago on Stack Overflow; I don’t think they’re affected by the meta tag.

The Service Manual also no longer requires testing on IE 8, so I do wonder if it's worth adding the tag at this point. (I believe IE 9 got rid of compatibility mode?)

[NickColley]

https://stackoverflow.com/questions/6771258/what-does-meta-http-equiv-x-ua-compatible-content-ie-edge-do

If I don't have "X-UA-Compatible" in headers, what would happen? – Morgan Cheng

Basically what happens is when you have the X-UA-Compatible it tells IE how to behave in regards to the value you set (IE=edge etc) if it is not there IE will show the site how it thinks best it should be shown. That could be compatibility mode or that could be the latest version of IE. Whatever Microsoft/IE thinks is best. Make sense?

This seems to confirm that having the tag would help any users using older IE...

[NickColley]

@paulwaitehomeoffice GOV.UK Frontend still supports IE8 as there are some services that still support IE8 for example in prisons (https://github.com/alphagov/govuk-frontend/issues/1026)

[paulwaitehomeoffice]

An old Microsoft blog post suggests that the meta tag does at least get rid of the compatibility mode button, so that sounds good.

[colinrotherham]

Yes, definitely add this.

For older Internet Explorer you'll either want the HTTP header or the tag. Otherwise people will accidentally click that compatibility view button like you.

The meta tag has higher priority, and can be compressed (gzip) unlike the header.

It's possible for intranet zone settings, custom enterprise lists (via directory group policies) or the official Microsoft Windows Update list to override it but it's a good default.

[36degrees]

For context, this was not present in GOV.UK Template – nor are there any mentions of it in GOV.UK Template's Git history (according to git log -S "X-UA-Compatible"). (Not to say it shouldn't be added)

It does appear to be in many GOV.UK apps.

[36degrees]

Resolved as part of #1116