I have an iframe, which displays a different height in different browsers (see screenshot below). I am adding an iframe (the same html code, css a little different) to about 20 Wordpress themes, and it works 100% fine on all the blogs except this one. It is set to a width of 4829 pixels, but for some reasong renders differently in Chrome, IE9 and Firefox. It is also not a metter of few pixels, but it looks like almost 200, and I have no idea where is it coming from. <iframe src="<?php echo get_template_directory_uri(); ?>/../../aside/personaltrainer.html" height="4829" width="220" frameborder="0">You need a frames capable browser to view this content.</iframe> Code (markup): If somebody has an idea what might be a reason for this one, please let me know. Thank you.