[HTML] div in div 2. ist zu groß

<div style="background-color:#000;border:1px solid red;width:702px;height:100% auto;"> 
 <div id="test" style="filter:Light(1);background-color:#000;width:700px;height:125px;"> 
 <img src="stepbystep.jpg"> 
 </div> 
 <div style="width: 700px; float: left;"> __ hier kommt dein inhalt rein __ </div> 
</div>

 /**
 * function getViewportSize()
 *
 * This function differentiates between browsers to get the viewport size. The size is returned as an array. The first value is the width and the second value is the height.
 *
 * @return array
 */
 function getViewportSize() {
 var size = [0, 0];//basic varray

 //browser differentiation for the viewport size
 if (typeof window.innerWidth != 'undefined') {//opera, gecko, netscape etc.
 size = [window.innerWidth, window.innerHeight];
 } else if ((typeof document.documentElement != 'undefined') && (typeof document.documentElement.clientWidth != 'undefined') && (document.documentElement.clientWidth != 0)) {//ie in standard mode through DTD
 size = [document.documentElement.clientWidth, document.documentElement.clientHeight];
 } else {//ie in quirks mode
 size = [document.getElementsByTagName('body')[0].clientWidth,
 document.getElementsByTagName('body')[0].clientHeight];
 }
 return size;
 }//end - function getViewportSize()

<script>
window.onload = function() {
 var fheight = window.innerHeight;
 document.getElementById('main').style.height = fheight + 'px';
 document.getElementById('content').style.height = (fheight-125) + 'px';
}
</script>
<div id="main" style="background-color:red;width:702px;">
 <div id="test" style="filter:Light(1);background:url(stepbystep.jpg);width:700px;height:125px;">

 asdf

 </div>
 <div id="content" style="text-align:left;background-color:#000;width:700px; color: white;">

 asdf2

 </div>
</div>

<script type="text/javascript">
window.onload = function() {
 var fheight = window.innerHeight;
 if(document.getElementById('main').offsetHeight < fheight) {
 document.getElementById('main').style.height = fheight + 'px';
 document.getElementById('content').style.height = (fheight-235) + 'px';
 }
}
</script>