function randBgImg () {
bodyB = document.getElementById('bbg');
var bg = ""
var randy = Math.random();
var stateSel = randy * 5;  //put in number of images to swap here and if more added add more cases below
stateSel = Math.ceil(stateSel);
switch (stateSel){
case 1:
	bg = "url(images_main/background.gif) top center"; //this line accepts a string, put in anything you would in a background style rule
	break;
case 2:
	bg = "url(images_main/background_1.gif) top center";
	break;
case 3:
	bg = "url(images_main/background_2.gif) top center";
	break;
case 4:
	bg = "url(images_main/background_3.gif) top center";
	break;
case 5:
	bg = "url(images_main/background_4.gif) top center";
	break;
}
bodyB.style.background = bg;


}