function clickIE(){
 if(document.all){return false}
}

function clickNS(e){
 if(document.layers||(document.getElementById&&!document.all)){
  if(e.which==2||e.which==3){return false}
 }
}

if(document.layers){
 document.captureEvents(Event.MOUSEDOWN);
 document.onmousedown=clickNS;
}else{
 document.onmouseup=clickNS;
 document.oncontextmenu=clickIE;
}

document.oncontextmenu=new Function("return false")