I know I must be missing something here, but I cannot seem to get this to work.
I have assigned a background color to the body of an html document using the style tags inside the head section of the document, but when I try to read it via JavaScript, I get nothing:
<html>
<head>
<style>
body { background-color: #ff0; }
</style>
</head>
<body>
<a href="#" onclick='alert(document.body.style.backgroundColor)'>Click Here</a>
</body>
</html>
.. however, if I assign the style inline, it works:
<html>
<head></head>
<body style='background-color: #ff0;'>
<a href="#" onclick='alert(document.body.style.backgroundColor)'>Click Here</a>
</body>
</html>
I know I am missing something basic, but my mind is not in the zone today -- can anyone tell me why my first scenario is not working?
Thanks
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stackoverflow.com/questions/1048336/…Maciej Łebkowski– Maciej Łebkowski2009年07月08日 14:17:00 +00:00Commented Jul 8, 2009 at 14:17
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Check this out: stackoverflow.com/questions/324486/…Peter– Peter2009年07月08日 14:17:57 +00:00Commented Jul 8, 2009 at 14:17
4 Answers 4
The style property of a DOM element refers only to the element's inline styles.
Depending on the browser, you can get the actual style of an element using DOM CSS
In firefox, for example:
var body = document.getElementsByTagName("body")[0];
var bg = window.getComputedStyle(body, null).backgroundColor;
Or in IE:
var body = document.getElementsByTagName("body")[0];
var bg = body.currentStyle.backgroundColor;
Comments
In this case, you'll want the computedStyle on the Element as the style attribute hasn't been set yet. In IE, you'll need to check the Element's currentStyle property, via something like this.
Comments
Here is a function you can use (without the use of a framework ie) that was posted here by InsDel:
function getStyle(className) {
var classes = document.styleSheets[0].rules || document.styleSheets[0].cssRules
for(var x=0;x<classes.length;x++) {
if(classes[x].selectorText==className) {
(classes[x].cssText) ? alert(classes[x].cssText) : alert(classes[x].style.cssText);
}
}
}
getStyle('.test')
Comments
That's just how css works. There's no straight-forward way to get the computed css attributes of an element within Javascript, that I know of, short of browser specific utilities.