Edit in JSFiddle

var div = document.getElementById('testDiv');
div.addEventListener('mousedown', function(e) {
		var isRightButton;
    e = e || window.event;

    if ("which" in e)  // Gecko (Firefox), WebKit (Safari/Chrome) & Opera
        isRightButton = e.which == 3; 
    else if ("button" in e)  // IE, Opera 
        isRightButton = e.button == 2; 

    alert("Right mouse button " + (isRightButton ? "" : " was not ") + "clicked!");
});

div.addEventListener('contextmenu', function(e) {
		e.preventDefault();
});

<div id="testDiv">
</div>

#testDiv {
  width: 200px;
  height: 200px;
  background-color: red;
}