function navover(id) {
      document.getElementById("nav_" + id).src = "/images/" + id + "_roll.gif";
}
   
function navout(id) {
      document.getElementById("nav_" + id).src = "/images/" + id + ".gif";
}

function buttonColor(id, color) {
   document.getElementById(id).style["color"] = color;
}

/*function enable(id, greyout) {
   document.getElementById(id).style["display"] = "block";
   if (greyout) {
	  buttonColor(id+"BTN", "#000000");
   }	
}
	
function disable(id, greyout) {
   document.getElementById(id).style["display"] = "none";
   if (greyout) {
	  buttonColor(id+"BTN", "#cccccc");
   }
}

function showText(id){
   for(elem in elems) {
	  disable(elems[elem], true);
   }
   
   enable(id, true);
};

function bringForward(id) {
   document.getElementById(id).style["z-index"] = 1;
}

function sendBack(id) {
   document.getElementById(id).style["z-index"] = 0;
}*/