enable mouse disabled by script

Hi,

I saw this website http://www.pesten.net/ where it is made imposible to select/copy text or open the context menu. What is the easiest way to enable it again?

This is the source responsible:

<script type="text/javascript" language="JavaScript">
<!--

function dno() {
  return false
}

function omu(e) {
  if(e.which==1){
    window.releaseEvents(Event.MOUSEMOVE);
    window.onmousemove=null
  }
}

function jk(){
  alert(unescape("This function is not available."));
  return false
}

function kj(e){
  if(e.which==1){
    window.captureEvents(Event.MOUSEMOVE);
    window.onmousemove=dno
  }
  if(e.which==3){
    return jk()
  }
}

function ct(){
  hg=event.button;
  if(hg==2||hg==3) jk()
}

vc=document.all;
qb=document.getElementById;

if(vc){
  if(qb){
    document.oncontextmenu=jk;
    document.onselectstart=dno;
    document.ondragstart=dno
  }else{
    document.onmousedown=ct
  }
}

if(qb&&!vc){
  document.onmousedown=dno;
  document.onmouseup=kj;
  document.oncontextmenu=dno
}

if(document.layers){
  window.captureEvents(Event.MOUSEUP|Event.MOUSEDOWN);
  window.onmousedown=kj;
  window.onmouseup=omu
}

function qa0(){
  window.status=" ";
  setTimeout("qa0()",50)
}

qa0();

function qa1(){
  return true
}

if(document.all||document.getElementById)
  document.body.onmouseover=qa1
//-->
</script>

I was able to solve it for myself using the javascript console in firebug, but don't want to do that each time and I want to explain it to a non-technical person using IE.