为什么我的DIV没有用,救命啊!!!!!!

各位XDJM,我下面的代码在一个JS文件里面,在ie下能正常显示,可是在firefox下那个div的宽度和高度不起作用,不管我改什么值都没有用,请各位指点一下,我快疯了
document.write('<div id="aa" style="Z-INDEX: -1; LEFT: 22.5%; VISIBILITY: visible;margin-left:auto; WIDTH: 720px;  POSITION: absolute; TOP: 0px;  HEIGHT:70px;"><object classid="clsid:D27CDB6E-AE6D-11cf-96B8-444553540000" codebase="http://download.macromedia.com/pub/shockwave/cabs/flash/swflash.cab#version=6,0,29,0" width=720px; height=70px;><param name="movie" value="admin/ad/200652591322.swf"><param name="quality" value="high"><embed src="admin/ad/200652591322.swf" quality="high" pluginspage="http://www.macromedia.com/go/getflashplayer" type="application/x-shockwave-flash"></embed><PARAM value="transparent" name="wmode"></object></div>')