function readMap ()
 {
     var map, i;
     // get array of map area tags
     map=document.getElementsByTagName('area');
     for(i=0;i<map.length;i++)
     {
     //add onmouseover and onmouseout event functions
     map[i].onmouseover=function(){shift(this);};
     map[i].onmouseout=function(){shift(this);};
     }
 }
 function shift (o)
 {
     var mapbg, id;
     //set id  variable to the 'id' of the area on the map where the mouse is positioned
     id = o.id;
     //the master object where the image map is used in this case a clear gif with the id 'mapimg'
     mapbg = document.getElementById('aam');
    //if the className and the id match reset the class to the default state -or- shift the background image to the correct position by using the new class value
    if(id == mapbg.className){
     mapbg.className='ap_euro_camper'; 
    }else{
     mapbg.className=id;
     }
 }
 window.onload=function(){
  readMap();
 }