Proportions

[max2474]

I have a DIV that changes size depending on a window size :
<div id="slidemarginleft" class="style2" style="right: 0%; top: 0px; position: fixed; width: 25%; height: 50%;">

It works fine, however I wonder if there is a way of keeping proportions. I want the height to be 75% of the width (eg. for a photo or video). You can see what i mean by looking at http://max2474.pcriot.com/slide.htm (Not much to look at yet :))

Is this possible?

[max2474]

you may need to use ie8 to see this. current video doesnt work in firefox, but as this will not be end content, am not worried about this atm.

thanks for any advice.