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opacity in IE8 depends on position:relative

I noticed that in some cases form elements cannot be made transparent in IE8. It turned out to depend on the position:relative CSS tag. The below HTML demonstrates the issue:

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>title</title>

<style type="text/css">

.ie-opaque {
    zoom : 1;
    -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
    filter: alpha(opacity=50);
}

.relative {
    position: relative;
}

</style>


</head>
<body>

    <div class="ie-opaque">
        <form>
        <fieldset>
        <ol>
            <li class="relative">
                <label for="test">label</label>
                <input id="test"/>
            </li>
            <li class="relative">
                <button>push</button>
            </li>
            <li>
                <label for="test">label</label>
                <input id="test"/>
            </li>
            <li>
                <button>push</button>
            </li>
        </ol>
        </fieldset>
        </form>
    </div>

</body>
</html>

In IE8 items 3 and 4 are transparent, 1 and 2 are not. Any idea why?

In Internet Explorer 7, 8, 9, non-static child elements do not inherit the opacity of the parent.

Workarounds:

  • IE9: Give the parent a non-static position.
  • IE8: Have the child inherit the filter style.
  • IE7: Have the child inherit the filter style and give the parent a non-static position.

Linked from here:

http://www.jacklmoore.com/notes/ie-opacity-inheritance

Using classes with "li" is bad practice as they were designed for listing similar information with a similar appearance, I'm assuming MS chose to ignore support for child elements with ie8 that use classes & id's that shouldn't.

I would suggest using pseudo classes (effects won't show on <=IE8 browsers), or javascript if you need to target specific li's.

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