Issue with CSS JQuery PHP Menu

Question

Recently i have launched one flash online gaming portal and its working perfectly. The major issue with the site is the site comes perfectly in Chrome, Opera, IE but in Firefox and Safari the jQuery CSS sliding menu is not coming properly. Its merging with the top div. Please refer this link and see the header part you will come to know the actual issue.

See below picture: Reference URL

Answer 1

before and after menu block you can add

<style>
.clear {
clear: both;
}
</style>

<div class="clear"></div>

Answer 2

Add clear: both to the .menu_container:

.menu_container {
background-color: #FFF;
width: 100%;
overflow: auto;
clear: both;
}

Answer 3

Your problem is the that "header" div has height 0. One way to fix it (checked in Firefox) is to set "height : 100%" on that div.