Invisible div over div does not work in IE8

Question

I'm trying to create an invisible div, over the facebook comments plugin in order to disable the plugin's functionality in an Editor View. This invisible div works in all browsers except IE8. How can I fix this?

HTML:

<div id="container">
   <div id="coveriframe"></div>   
    <div data-bind-component="fbml: fbml">(RENDER JS COMMENTS VIA KO)</div>
</div>

Try in IE8:

http://jsfiddle.net/pkbz4/19/

• The above code works in ALL other Major browsers. WTF Microsoft?

Stylesheet:

    #container {
        width: 100%;
        height: 100%;
        position: relative;
    }

    #navi, 
    #coveriframe {
        width: 100%;
        height: 100%;
        position: absolute;
        top: 0;
        left: 0;
    }

    #coveriframe {
        z-index: 10;
   }

Answer 1

I've done this several times in IE8. The solution that works for me is to assign a background color to the div and then set opacity to 0. IE8 then recognizes the div as "existing" above the rest of the content. I also find setting position: absolute and all four directions to 0 is more reliable than 100% width and height. Like this:

#coveriframe {
  position: absolute;
  top: 0; 
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 3007;
  background: #fff;
  filter: alpha(opacity=0);
  opacity: 0;
}

Here's my update to your jsfiddle: http://jsfiddle.net/pkbz4/21/

Answer 2

CSS Specification says:

The percentage is calculated with respect to the height of the generated box's containing block. If the height of the containing block is not specified explicitly (i.e., it depends on content height), and this element is not absolutely positioned, the value computes to 'auto'.

Basically, In older versions of IE (including IE8) percentage heights are based on the height of the parent element. If the parent element doesn't have an explicit height, the percentage is ignored and set to Auto (in this case, 0px).

So, to fix this, you'll either want to explicitly set the height/width of #coveriframe or its parent. One thing you could try is setting the height of html and body to 100% (I'm assuming those are the parent elements).

html, body { height:100%; }

#container {
    width: 100%;
    height: 100%;
    position: relative;
}

#navi,
#coveriframe {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
}

#coveriframe {
    z-index: 10;
}