add1 = '<a href="http://www.halfadot.com" target="portfolio"><img src="../common/card-1.gif" border="0" alt="web design and development from halfadot: specialists in small business" /></a>'
+ '</a>';
add2 = '<a href="http://www.halfadot.com" target="portfolio"><img src="../common/card-2.gif" border="0" alt="web design and development from halfadot: specialists in small business" /></a>'
+ '</a>';
add3 = '<a href="http://www.halfadot.com" target="portfolio"><img src="../common/card-5.gif" border="0" alt="web design and development from halfadot: specialists in small business" /></a>'
+ '</a>';
add4 = '<a href="http://www.halfadot.com" target="portfolio"><img src="../common/card-6.gif" border="0" alt="web design and development from halfadot: specialists in small business" /></a>'
+ '</a>';
add5 = '<a href="http://www.digitalmidget.com" target="portfolio"><img src="../common/card-3.gif" border="0" alt="web design and development from halfadot: specialists in small business" /></a>'
+ '</a>'
add6 = '<a href="http://www.digitalmidget.com" target="portfolio"><img src="../common/card-4.gif" border="0" alt="web design and development from halfadot: specialists in small business" /></a>'
+ '</a>';
//The number below, must be the same as the number of banners you have.
addnum = Math.floor(Math.random() * 6) + 1;

document.write(eval("add" + addnum));