var clickmessage="Right click disabled on images!";

function disableclick(e) {
	if (document.all) {
		if (event.button==2||event.button==3) {
			if (event.srcElement.tagName=="IMG"){
				alert(clickmessage);
				return false;
			}
		}
	} else if (document.layers) {
		if (e.which == 3) {
			alert(clickmessage);
			return false;
		}
	} else if (document.getElementById){
		if (e.which==3&&e.target.tagName=="IMG"){
			alert(clickmessage);
			return false
		}
	}
}

function associateimages(){
	for(i=0;i<document.images.length;i++) {
		document.images[i].onmousedown=disableclick;
	}
}

if (document.all) {
	document.onmousedown=disableclick;
} else if (document.getElementById) {
	document.onmouseup=disableclick;
} else if (document.layers) {
	associateimages();
}