old webpages don't work as expected in IE11 when i add the site to compatibility view settings manually. But when I debug the website(F12) and Emulate it in IE7 ot IE5,it work well.

Question

Hi,

As I said in the title, I have some apps that are a bit on the older side, and will not get upgraded. and they work only in IE version under 8(8 not included) (No other browsers).

Now I need to use it in IE11.

Step1:

I debug the website, f12. When I visit a web page, the console print "attachEvent properties or methods are not supported" on the login screen.

Step2:

Then I add the website to compatibility view settings manually. At this time , the console doesn't print error on the login screen, but after I logging in and clicking to other page(still under this website),the console print such as "attachEvent properties or methods are not supported" again.

I click the Emulation tab, and find that the "Document Mode" is "5(default)" now.

Step3:

And then I change it to "7", surprisingly, the website can work well.

Step4:

So, I cancel the compatibility view settings and set the response head to "X-UA-Compatible IE=7".

Now, the "Document Mode" is "7(default)" . But as "Step2", it still doesn't work well.At this time, I try to change "Document Mode" to "5", Amazing! the website can work well.

Step 5:

I cancel the compatibility view settings and don't set the response head.

Now , the "Document Mode" is "11(default)", then I change it to "5" or "7",both can work well.

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So, could you please give me some suggests on how to use this websit well in IE11.

Thank you!