var EventHandlerEnabled = true;

function movepic(img_name,img_src,lbl_name,lbl_txt) {
 if(EventHandlerEnabled) {
  document[img_name].src=img_src;
  document.getElementById('label1').innerHTML = lbl_txt;
}
return true;
}

function disableEvent(){
window.EventHandlerEnabled = false;
}

function enableEvent(){
window.EventHandlerEnabled = true;
}