var img=new Array("http://www.mscorporation.com/wp-content/themes/mscorp/images/main_01.jpg","http://www.mscorporation.com/wp-content/themes/mscorp/images/main_02.jpg","http://www.mscorporation.com/wp-content/themes/mscorp/images/main_03.jpg");
document.write('<img src="'+img[Math.floor(Math.random()*img.length)]+'" border="0" />');