function MM_findObj(n, d) {
	//v4.0
	var p,i,x;  if(!d) d=document; if((p=n.indexOf("?"))>0&&parent.frames.length) {
		d=parent.frames[n.substring(p+1)].document; n=n.substring(0,p);
	}
	if(!(x=d[n])&&d.all)
		x=d.all[n];
		for (i=0;!x&&i<d.forms.length;i++)
			x=d.forms[i][n];
		for(i=0;!x&&d.layers&&i<d.layers.length;i++)
			x=MM_findObj(n,d.layers[i].document);
		if(!x && document.getElementById)
			x=document.getElementById(n);
			return x;
}
function MM_showHideLayers() {
	//v3.0
	var i,p,v,obj,args=MM_showHideLayers.arguments;
		for (i=0; i<(args.length-2); i+=3)
			if ((obj=MM_findObj(args[i]))!=null) {
				v=args[i+2];
			if (obj.style) {
				obj=obj.style; v=(v=='show')?'visible':(v='hide')?'hidden':v; }
		obj.visibility=v; }
}

function hide_all() {
	MM_showHideLayers('blue_img','','hide');
	MM_showHideLayers('red_img','','hide');
	MM_showHideLayers('green_img','','hide');
	MM_showHideLayers('orange_img','','hide');
}