CSS Workarounds for Internet Explorer < 7

After laying out a site with CSS, there are still some things that don't work as intended in IE < 7. Here are some fixes gleaned from various pages:

Apply CSS only to IE < 7

Use conditional comments:

<!--[if lt IE 7]>
<style type="text/css">
  CSS HERE
</style>
<script language="javascript">
  JAVASCRIPT HERE
</script>
<![endif]-->

Support min-height

Use height, which is treated as if it's min-height in IE:

#item{
  height: 30em;
}

Emulate max-width

Use expression, which runs only in IE:

#item{
  width:expression(
    document.body.clientWidth > (500/12) * parseInt(document.body.currentStyle.fontSize) ? "30em": "auto"
  );
}

Support position: fixed

Use position: absolute and expression:

#item{
  position: absolute;
  top: expression(eval(document.body.scrollTop));
}

Transparent PNGs

Use Javascript to add IE-specific filters to all the PNGs in the page:

function correctPNG() // correctly handle PNG transparency in Win IE 5.5 & 6.
{
   var arVersion = navigator.appVersion.split("MSIE")
   var version = parseFloat(arVersion[1])
   if ((version >= 5.5) && (document.body.filters)) 
   {
      for(var i=0; i<document.images.length; i++)
      {
         var img = document.images[i]
         var imgName = img.src.toUpperCase()
         if (imgName.substring(imgName.length-3, imgName.length) == "PNG")
         {
            var imgID = (img.id) ? "id='" + img.id + "' " : ""
            var imgClass = (img.className) ? "class='" + img.className + "' " : ""
            var imgTitle = (img.title) ? "title='" + img.title + "' " : "title='" + img.alt + "' "
            var imgStyle = "display:inline-block;" + img.style.cssText 
            if (img.align == "left") imgStyle = "float:left;" + imgStyle
            if (img.align == "right") imgStyle = "float:right;" + imgStyle
            if (img.parentElement.href) imgStyle = "cursor:hand;" + imgStyle
            var strNewHTML = "<span " + imgID + imgClass + imgTitle
            + " style=\"" + "width:" + img.width + "px; height:" + img.height + "px;" + imgStyle + ";"
            + "filter:progid:DXImageTransform.Microsoft.AlphaImageLoader"
            + "(src=\'" + img.src + "\', sizingMethod='scale');\"></span>" 
            img.outerHTML = strNewHTML
            i = i-1
         }
      }
   }    
}
window.attachEvent("onload", correctPNG);