1. protocol relative URLs
“Internet explorer does not
like mixers”

2. The problem CSS, Images and Styleheets called via fully qualified URL
<link type=“text/css” href=“
@import url(‘
background-image { url(‘
<img src=“
<script src=“
If page is loaded via connection then the page will contain mixed content, i.e. the page will be encrypted but the content above will be unencrypted
So what you may ask!

3. The solution Drop the http: <link type=“text/css” href=“//
background-image { url(‘//
<img src=“//
<script src=“//
Example:

4. Details Caveats Read more
Remember any assets (stylesheets, images etc) being called must available via both http and https
There is a small bug with IE7 & IE8:
When used with <link> the requested css file will be downloaded twice
Read more