var ie=document.all;
var nn6= document.getElementById&&!document.all ;
var firefox = navigator.userAgent.indexOf("Firefox")!=-1;
var isswitch=false;
var x,y;
var dobj;
var tx,ty;
var currentpic = 4;
var medelvindon = true;
var maxvindon = false;

function selectmouse(e) 
{
  var fobj       = nn6 || firefox ? e.target : event.srcElement;
  var topelement = nn6 || firefox ? "HTML" : "BODY"; 

  while (fobj != null && fobj.tagName != topelement && (fobj.id.search("knappdiv")==-1) && fobj.id != "medelvind" && fobj.id != "maxvind")
  {
    fobj = nn6 || firefox ? fobj.parentNode : fobj.parentElement;
  }
  
  if (fobj != null && fobj.id=="medelvind"){
	  if(medelvindon){
	  	document.getElementById("medelvind").src = "images/medelvindoff.gif";
		document.getElementById("averagegraph").style.zIndex = 0;
		medelvindon = false;
	  }else{
        document.getElementById("medelvind").src = "images/medelvindon.gif";
				document.getElementById("averagegraph").style.zIndex = 3;
		medelvindon = true;
	  }
  }
  if (fobj != null && fobj.id=="maxvind"){
	  if(maxvindon){
	  	document.getElementById("maxvind").src = "images/maxvindoff.gif";
		document.getElementById("maxgraph").style.zIndex = 0;
		maxvindon = false;
	  }else{
        document.getElementById("maxvind").src = "images/maxvindon.gif";
		document.getElementById("maxgraph").style.zIndex = 3;
		maxvindon = true;
	  }
  }


  <!-- code fore the switch -->
   if (fobj != null && fobj.id.search("knappdiv")!=-1){
//	   isswitch = true;
//	    x = nn6 || firefox ? e.clientX : event.clientX;
//    	y = nn6 || firefox ? e.clientY : event.clientY;	
		flipSwitch();
	    return false;
   }
}

function onImgError(source) {
  source.src = "images/sssr.gif";
  // disable onerror to prevent endless loop
  source.onerror = "";
  return true;
}

   <!--End  code fore the switch -->
  function flipSwitch(){

	  		if(currentpic == 4){			
				document.getElementById("knappdiv1").style.zIndex="4";
				document.getElementById("knappdiv2").style.zIndex="1";
				document.getElementById("knappdiv3").style.zIndex="1";
				document.getElementById("knappdiv4").style.zIndex="1";
				
				document.getElementById("webcamdiv1").style.zIndex="4";
				document.getElementById("webcamdiv2").style.zIndex="1";
				document.getElementById("webcamdiv3").style.zIndex="1";
				document.getElementById("webcamdiv4").style.zIndex="1";
				

//				document.getElementById("webcambild").src = "http://valle.webcamtoddy.com/~cakalmar/ca_kalmar_1_320.jpg";
				currentpic = 1;
				return false;
		}
		if(currentpic == 1){
				document.getElementById("knappdiv1").style.zIndex="1";
				document.getElementById("knappdiv2").style.zIndex="4";
				document.getElementById("knappdiv3").style.zIndex="1";
				document.getElementById("knappdiv4").style.zIndex="1";
				
				document.getElementById("webcamdiv1").style.zIndex="1";
				document.getElementById("webcamdiv2").style.zIndex="4";
				document.getElementById("webcamdiv3").style.zIndex="1";
				document.getElementById("webcamdiv4").style.zIndex="1";
				
				
//				document.getElementById("webcambild").src = "http://www.kronocampingoland.se/saxnasturism/ispy.jpg";
				currentpic = 2;
				return false;
		}
		if(currentpic == 2){
				document.getElementById("knappdiv1").style.zIndex="1";
				document.getElementById("knappdiv2").style.zIndex="1";
				document.getElementById("knappdiv3").style.zIndex="4";
				document.getElementById("knappdiv4").style.zIndex="1";
				
				document.getElementById("webcamdiv1").style.zIndex="1";
				document.getElementById("webcamdiv2").style.zIndex="1";
				document.getElementById("webcamdiv3").style.zIndex="4";
				document.getElementById("webcamdiv4").style.zIndex="1";
				
				
//		document.getElementById("webcambild").src = "http://trafiken.nu/VSO/bilder/400.JPG";
		currentpic = 3;
		return false;
		}
		if(currentpic == 3){
				document.getElementById("knappdiv1").style.zIndex="1";
				document.getElementById("knappdiv2").style.zIndex="1";
				document.getElementById("knappdiv3").style.zIndex="1";
				document.getElementById("knappdiv4").style.zIndex="4";
				
				document.getElementById("webcamdiv1").style.zIndex="1";
				document.getElementById("webcamdiv2").style.zIndex="1";
				document.getElementById("webcamdiv3").style.zIndex="1";
				document.getElementById("webcamdiv4").style.zIndex="4";
				
				
//		document.getElementById("webcambild").src = "http://www.owc.nu/webcam/webcam320.jpg";
		currentpic = 4;
		return false;
		}
  }
  

function mouseup() {
//                isswitch = false;
}

//function loadit(){
//document.getElementById("table1").style.top="0px;";
//}

//document.onload=loadit;
document.onmousedown=selectmouse;
document.onmouseup=mouseup;

<!-- END Code for drag and drop -->