[RESOLVED] Detect Dynamic DIV Values?

[toomzee]

Is it possible to detect the actual height of a dynamic DIV that has its height set to :auto after the PHP has been processed? Say for example you have a left column and a right column. The left column is a news story, or a blog post, whatever... the right column is a sidebar, and you have content in both. The left column height is defined by the content, so if it is a long news story, the left DIV will be taller, if it is only one paragraph it won't make it very tall, right? Is it possible to detect the height that it stretches to? The reasoning would be that say the right sidebar had content that is 400px tall. I'd like to display optional content below that, like a tower ad or a poll, but only if that content would end up about the same height as the left column overall, or thereabouts. This would avoid having a tower ad or poll that extended well below the article and not get seen.

Say the right sidebar content is 400px tall and the tower ad is another 400px tall. I want to basically enact this;

if ($leftcol_height > 800px)
{
show ad
}
else
{
don't show ad
}

any ideas on how to do this server side or client side even?

[NogDog]

Since the rendering is done by the client, not by the server where your PHP is running, you cannot know exactly at what size an element will be rendered. You could make some educated guesses by counting characters and doing a bit of math, but it will never be perfectly accurate and could end up being off by quite a bit if the user has display settings that override your document's styles (e.g. base font size).

[toomzee]

Hmmm... what about passing this JavaScript value to PHP?

var height = document.getElementById('post_entry').style.height;

[toomzee]

I got it working through trial and error.

<script type="text/javascript">
<!--
onload=function() {
var postheight = document.getElementById('post_entry').offsetHeight;
if (postheight < 800)
{
document.getElementById('sidebarad').style.visibility = 'hidden';
}
else
{
document.getElementById('sidebarad').style.visibility = 'visible';
}
}
//-->
</script>