function startdrag(t, e) {  
    if (e.preventDefault) e.preventDefault(); //line for IE compatibility  
    e.cancelBubble = true;  
    window.document.onmousemoveOld = window.document.onmousemove;  
    window.document.onmouseupOld = window.document.onmouseup;  
    window.document.onmousemove=dodrag;  
    window.document.onmouseup=stopdrag;  
    window.document.draged = t;  
    t.dragX = e.clientX;  
    t.dragY = e.clientY;  
    return false;  
}  
//move the DIV  
function dodrag(e) {  
      
    if (!e) e = event; //line for IE compatibility  
    t = window.document.draged;  
    t.style.left = (t.offsetLeft + e.clientX - t.dragX)+"px";  
    t.style.top = (t.offsetTop + e.clientY - t.dragY)+"px";  
    t.dragX = e.clientX;  
    t.dragY = e.clientY;  
    return false;  
}  
//restore event-handlers  
function stopdrag() {  
   window.document.onmousemove=window.document.onmousemoveOld;  
   window.document.onmouseup=window.document.onmouseupOld;  
}  

function thumbmouseover(divnaam){
	document.getElementById(divnaam).style.backgroundImage ='url("http://www.grafitek.nl/site/images/bg-thumbon.png")'; }
function thumbmouseout(divnaam){
	document.getElementById(divnaam).style.backgroundImage ='url("http://www.grafitek.nl/site/images/bg-thumboff.png")';  }
	
function resizegt(){
	if (pageHeight()<660) document.getElementById("content").style.marginTop="90px";
	else document.getElementById("content").style.marginTop="140px";
}

function pageHeight() {return window.innerHeight != null? window.innerHeight : document.documentElement && document.documentElement.clientHeight ?       document.documentElement.clientHeight : document.body != null ? document.body.clientHeight : null;}