Removes Default Drag Behaviour On Image In Netscape

I am trying to implement a rubber band/image selection script. For
that I need to remove the default drag behaviour on an image. I am
able to do this in IE but not Netscape. Does any one have a solution?

Pls look below for IE code:

var moz = ((document.all)? false : true);
var ie = ((document.all)? true : false);
var ElementUtil = new Object();
ElementUtil.addEventListener = function(o, type, handler) {
if(ie) {
o.attachEvent("on" + type, handler);
}
else if(moz) {
o.addEventListener(type, handler, false);
}
}

// Removes default drag behaviour on image in ie
ElementUtil.addEventListener(img, "drag", function() {return false;});