nav = document.layers;
IE4 = document.all;

isNav4 = (nav) ? true : false;
isIE4 = (IE4) ? true : false;

if(isNav4){

     function allobj(ID){ 

          this.style = document.layers[ID];            
       }
document.all = new Array(); 
 }

function init(){ 
        if(isNav4){ 
                 end = document.layers.length;
            for(i=0; i < end; i++){
            id = document.layers[i].name;
            document.all[id] = new allobj(id);
             }                     
        }
  } 

function catchEvent(id,event_type,function_name){

if (isNav4){
     event_to_capture = "Event." + event_type.toUpperCase();
     
     if(id=="document"){
     dom = document;
      eval("document.captureEvents(" + event_to_capture + ")");

     }else{ 
        
        dom = document.layers[id];
        eval("document.layers['" + id + "'].captureEvents(" + event_to_capture + ")");

     }
}
else if(isIE4){

if(id == "document"){

dom = document;
}else{

       dom = document.all[id];
}
}
        temp_event = "on" + event_type.toLowerCase();
        dom[temp_event] = eval(function_name);
}


function letgoEvent(id,event_type,function_name){

if (isNav4){

        dom = document.layers[id];
       
}
else if(isIE4){
       dom = document.all[id];
}
        temp_event = "on" + event_type.toLowerCase();
        dom[temp_event] = null;
}