//randomizer.Generate random numbers。
rnd.today=new Date(); 
rnd.seed=rnd.today.getTime(); 
    function rnd() { 
　　　　rnd.seed = (rnd.seed*9301+49297) % 233280; 
　　　　return rnd.seed/(233280.0);
    }; 
    function rand(number) { 
　　　　return Math.ceil(rnd()*number); 
    }; 

//Change header image by radomized numbers
var n=rand(7);
if(n==0){
document.getElementById("header").style.backgroundImage="url(2009_home/pr.png)";
}
else if (n==1){
document.getElementById("header").style.backgroundImage="url(2009_home/pr_1.png)";
}else if (n==2){
document.getElementById("header").style.backgroundImage="url(2009_home/pr_2.png)";
}else if (n==3){
document.getElementById("header").style.backgroundImage="url(2009_home/pr_3.png)";
}else if (n==4){
document.getElementById("header").style.backgroundImage="url(2009_home/pr_4.png)";
}else if (n==5){
document.getElementById("header").style.backgroundImage="url(2009_home/pr_5.png)";
}else if (n==6){
document.getElementById("header").style.backgroundImage="url(2009_home/pr_6.png)";
}else if (n==7){
document.getElementById("header").style.backgroundImage="url(2009_home/pr_7.png)";
};