var Roll=new Array();

function RollOver(on_url)
{       this.on        = new Image();
        this.on.src    = on_url;
}

function flip ()
{       if(arguments.length==1) arguments[1]=arguments[0];
        for(i=0 ; i<arguments.length ; i+=2){
                temp = document.images[arguments[i]].src;
                document.images[arguments[i]].src  = Roll[arguments[i+1]].on.src;
                Roll[arguments[i+1]].on.src = temp;
        }
}

Roll["news"]    = new RollOver("images/news_on.jpg");
Roll["gallery"]    = new RollOver("images/gallery_on.jpg");
Roll["bio"]    = new RollOver("images/bio_on.jpg");
Roll["store"]    = new RollOver("images/store_on.jpg");
Roll["blog"]    = new RollOver("images/blog_on.jpg");
Roll["email"]    = new RollOver("images/email_on.jpg");