Umbruch nach jedem nth Child bei Floating Boxes
.innerBox:nth-child(4n+1){
clear: left;
}
Menü mit Submenü bei Hover
<div id="topnav">
<ul id="topnavList">
<li>
Link1
<ul class="subNavList" id="subNavList1">
<li>Sublink1</li>
<li>Sublink2</li>
<li>Sublink3</li>
</ul>
</li>
<li>
Link2
<ul class="subNavList" id="subNavList2">
<li>Sublink4</li>
<li>Sublink5</li>
<li>Sublink6</li>
</ul>
</li>
<li>
Link3
<ul class="subNavList" id="subNavList3">
<li>Sublink7</li>
<li>Sublink8</li>
<li>Sublink9</li>
</ul>
</li>
</ul>
</div>
#topnav>ul>li{
list-style: none;
display: inline;
position: relative;
}
.subNavList{
opacity: 0;
position: absolute;
list-style: none;
left: 0;
}
#topnav>ul>li:hover .subNavList{
opacity: 1;
}