function $(element){
    return document.getElementById(element);
}
function zoomPhoto(element, photo){
    $(element).src = "photos/" + photo;
}

function zoomPlan(element){
   var source = $(element).src;
   if(source.indexOf("1.gif")>0){
       $(element).src = "template/img/plan_2.gif";
   }
   else{
       $(element).src = "template/img/plan_1.gif";
   }
}