var timeout = 0;

  function swapMsImg(id) {
    document.master.src = '../images/products/circle_swo.jpg';
    clearTimeout(timeout);
    document.master.src = '../images/products/' + id + '.jpg'; 
  }

  function resetMsImage() {
    clearTimeout(timeout);
    timeout = setTimeout("swapMsDefault()", 750);
  }

  function swapMsDefault() {
    document.master.src = '../images/products/main_' + product + '_1.jpg';  
  }
	
	function getRand(n) {
  	rnd = Math.floor(Math.random() * n);
  	if (rnd < 1) {
    	getRand(n);
  	}
  	return rnd;
	}
	
	var imageIds = new Array(0, 'main_1', 'main_2', 'main_3', 'main_4');
	
	var rnd = getRand(imageIds.length);