How to dynamically change CSS elements to be HTTPS or HTTP

I have CSS with background-image's elements that refer to another site. Problem is, that in IE you can't have resources if you are in HTTP while they are in HTTPS and vise versa.

I am using ASP.NET and I want to find a way of letting the CSS know about if it was requested in HT开发者_开发问答TPS or NOT...

And I MUST use absolute... (its on a different site)

Thanks!

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Just omit the protocol (http: or https:) in your URLs: //domain/path/image.png will use the same protocol as the current page.

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The solution would be if you can use relative url instead of absolute in your CSS file while pointing background images.

The problem will gone.

something like:-

#div
{
  background-image:url(../images/img1.png);
}