Positing div in footer

Question

Hi i don't know how to center div in footer or float it right or left because my footer falls apart. Here is my code:

<div id="footer"><div id="tab_brand"><ul>
<li><a href="#"><img src="footer_slike/dell_footer.png"/></a></li>
</ul>
<ul>
<li><a href="#"><img src="footer_slike/acer_footer.png"/></a></li>
</ul></div>
</div>

css code

#footer{
background-color:grey;
width:100%;
height:auto;
margin:0;
padding:0;
left:0;
clear:both;
opacity:0.8;
}
#tab_brand{
height:100%;
left: 20px;
border:1px solid white;
}
#tab_brand ul li img{
padding:5px;
}
#tab_brand ul{
display: inline-table;
list-style: none;
height:auto;
width:auto;   
}

thanks

Answer 1

If you want to center #tab_brand you need to set a width to it and add "margin: 0 auto" to center it. Here is an example: http://jsfiddle.net/ok7Lyp2n/