function roll(obj,type)
{
	if (type == "on")
		obj.src = obj.src.replace("_off","_on");
	else
		obj.src = obj.src.replace("_on","_off");
}

function getVar(variable) {
  var query = window.location.search.substring(1);
  var vars = query.split("&");
  for (var i=0;i<vars.length;i++) {
    var pair = vars[i].split("=");
    if (pair[0] == variable) {
      return pair[1];
    }
  } 
  return "-1";
}