What is the difference between IE 10 Quirks and Internet Explorer 5 Quirks?

Question

What is the difference between Quirks Mode and Query Internet Explorer 5 in IE10 developer tools, JavaScript and CSS-wise?

Which of these two modes can be launched from HTML (unlike devtools)?

I read this blog post on MSDN, but couldn't figure out when this IE5 quirks mode can work on real websites. It says that all they need to do is not include doctype, and the browser should be in the compatibility view. Is the latter included manually or via HTML or what?

I am the author of the plugin and I am worried that other people have my plugin broken in document / browser mode.

Answer 1

In versions of IE prior to IE10, there is only one Quirks mode. This mode is now known as IE5 Quirks in IE10 and higher.

IE10 introduces a second Quirks mode, which it just calls Quirks.

Both of these modes change the rendering mode to use the old quirks window model, among other layout changes. This agrees a lot between the two.

The original Quirks mode was basically a backward compatibility mode for emulating IE5. Because of this, in addition to changing the model of the box, etc., It also disables most of the browser functions that were introduced with IE5 - therefore, in this mode, none of the new HTML5 functions will work.

The new Quirks mode uses the same rendering rules as the old quirks mode, but all browser features are not disabled.

This is the main difference between the two.

Then you can ask a question about why worry about having both modes?

The answer to this question is that other browsers (e.g. Chrome) also have Quirks mode, which runs (like IE) when the page is not of the doctype type. But other browsers have never disabled any of their features for backward compatibility in how IE did it.

The result was that a site in quirks mode could look different in IE compared to other browsers, even when the basic rendering rules were the same.

A new quirks mode was introduced by IE to improve cross-browser compatibility for quirks sites.

But as a result, the new quirks mode will display some pages differently in the older quirks mode, so the old one was still necessary for MS to support users whose sites were written for it.

Ultimately, if at all possible, you should avoid using the quirks mode (any of them). Despite the cross-browser efforts of MS introducing additional mode, there are still significant differences between browsers when you are in quirks mode.

Best practice is to always use the standards mode where possible.

Quirks mode is not needed anyway: if you need a model of the Quirks mode window, you can access it in standard mode using CSS box-sizing:border-box .