Only load the background-image when it has been fully loaded?

Question

Well, the title pretty much describes my question:

How to load the background-image dynamically after it has been fully loaded? Sometimes, I must use backgrounds that are so big that it can take a while for the browser to download it. I'd rather 'load it in the background' and let it fade in when it has been fully loaded.

I think jQuery would be best to be using, but I also want my background to appear if JavaScript has been disabled. If this really isn't possible, so be it, but I think it is?

Best regards, Aart

........

EDIT:

Thanks a bunch, guys! I've been bugged with this for ages and just couldn't think of a nice and easy way.

I converted Jeffrey's Javascript-solution into a jQuery one, just because jQuery's built-in fade looks so awesome.

I'll just post it here in case anyone else has the same issue:

<script type='text/javascript' src='http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js'></script>
<script type='text/javascript'>
    $(document).ready(function() {
        $('#img').css('opacity','0').load(function() {
            $(this).animate({
                opacity: 1
            }, 500);
        });
    });

</script>

<img src='yourimage.jpg' id='img'/> 

Answer 1

If the image is included with an img element:

<img src="bg.jpg" id="img" onload="this.style.opacity='1'">

<script>
    document.getElementById("img").style.opacity="0";
</script>

That should load the image normally if JavaScript is disabled, but show it only once it loads assuming it's enabled.

One thing to note (that I overlooked): some browsers will not even attempt to load an image if its display property is none. That's why this method uses the opacity attribute.