var images=new Array(); 
images[0]="header/1.jpg"; 
images[1]="header/2.jpg"; 
images[2]="header/3.jpg"; 
images[3]="header/4.jpg"; 
images[4]="header/5.jpg"; 
images[5]="header/6.jpg"; 
images[6]="header/7.jpg"; 
images[7]="header/8.jpg"; 
images[8]="header/9.jpg"; 
images[9]="header/10.jpg"; 
images[10]="header/11.jpg"; 
images[11]="header/12.jpg"; 


function randomimage() { 
var i=Math.floor(Math.random()*images.length); 
document.getElementById("random").src=images[i]; 

} 
onload=randomimage;