html - Dropdown menu doesnt overlapping with the container div -

i start make web page , meet problem: iframe in wanna put content overlapping menu. menu works fine till now, when put iframe

<div id="content">       <iframe name="content" frameborder="0" style="overflow: hidden; height: 100%; width: 100%; position: absolute;" height="100%" width="100%" seamless="seamless"></iframe> </div> 

and css is:

#content{     margin-top:77px;     margin-left:-10px;     position:absolute;         } 

what wrong? take of elements website , doesn't know doing wrong. menu working without div think div problem. announce me if need more details.