top.Navwin = self;
function roll(name,over){
	if(top.Navwin.document.images) {
		if (over)
			top.Navwin.document.images[name].src = "imag/" + name + "_on.gif";
		else
			top.Navwin.document.images[name].src = "imag/" + name + ".gif";
	}
}

var myimages=new Array()
function preloadimages(){
	for (i=0;i<preloadimages.arguments.length;i++){
	myimages[i]=new Image()
	myimages[i].src=preloadimages.arguments[i]
	}
}

preloadimages("imag/b1_on.gif","imag/b2_on.gif","imag/b3_on.gif")