JavaScript Tutorial/Style/getPropertyValue
Get style value by property value (IE does not support DOM style methods)
<html>
<head>
<title>Style Example</title>
<script type="text/javascript">
function useMethods() {
var oDiv = document.getElementById("myDiv");
alert(oDiv.style.getPropertyValue("background-color"));
}
</script>
</head>
<body>
<div id="myDiv" style="background-color: red; height: 50px; width: 50px"></div><br />
<input type="button" value="Use Methods" onclick="useMethods()" />
</body>
</html>