Rating Demystified: Ajax Way, Amazon Way*

	var starImages = new Array("images/0star.gif",
	"images/1star.gif",
	"images/2star.gif",
	"images/3star.gif",
	"images/4star.gif",
	"images/5star.gif");
	var nullStarMessage = "images/0.gif"
	var starMap = new Array('0,0,22,20',
	'23,0,36,20',
	'37,0,50,20',
	'51,0,64,20',
	'65,0,78,20',
	'79,0,101,20');
	var starMessages = new Array("images/0.gif",
	"images/1.gif",
	"images/2.gif",
	"images/3.gif",
	"images/4.gif",
	"images/5.gif",
	"images/saved.gif");

	var savedRatings = new Array();
	var changedRatings = new Array();
	var starTwinkler = new Array();
	var msgTwinkler = new Array();
	var isRatingsBarChanged = false;
	var delayTime = 500;
	var allImages = new Array();
function preloadImages(){
for (i=0; i < preloadImages.length ;i++){
	allImages[i] = new Image();
	allImages[i].src = preloadImages.arguments[i];
	}
}
preloadImages(starImages);
preloadImages(starMessages);

function SaveRating(id, ratingType, ratingValue){

	var submitURL = ''
	+ 'rated.aspx?'
	+ 'id=' + id
	+ '&Rating=' + ratingValue ;

	isRatingsBarChanged = true;
	window.location.href = submitURL;
}
function SwapStars(id, rating){
	if (rating == undefined){
	rating = savedRatings[id];
	}
	document.images["stars." + id].src = starImages[rating];
}
function SwapStarMsg(id, rating){
	if (rating == undefined){
	if ( changedRatings[id] ) {
	document.images["messages." + id].src = starMessages[6];
	} else {
	document.images["messages." + id].src = nullStarMessage;
	}
	} else {
	document.images["messages." + id].src = starMessages[rating];
	}
}
function SaveStars(id, rating){

if ((rating==1)||(rating==2)||(rating==3)||(rating==4)||(rating==5))
	{
	savedRatings[id] = rating;
	changedRatings[id] = 1;
	SaveRating(id, 'onetofive', rating);
	SwapStarMsg(id, 6);	}
	else
	{
	alert("Rating Value out of the bound, Values can only be 1/2/3/4/5. Current rating value: " + rating);
	}
}

function StarMouseOver(id, rating){
	if (starTwinkler[id] != 0){
	window.clearTimeout(starTwinkler[id]);
	starTwinkler[id] = 0;
}
if (msgTwinkler[id] != 0){
	window.clearTimeout(msgTwinkler[id]);
	msgTwinkler[id] = 0;
	}
	SwapStars(id, rating);
	SwapStarMsg(id, rating); 
}
function StarMouseOut(id){
	starTwinkler[id] = window.setTimeout("SwapStars('"+id+"')", delayTime);
	msgTwinkler[id] = window.setTimeout("SwapStarMsg('"+id+"')", delayTime);
}
function DisplayStars (id, rating){
	var starID = "stars." + id;
	starTwinkler[id] = 0;
	msgTwinkler[id] = 0;
	document.write("<map name='starmap" + id +"'>");
	var i = 0;
	for (i = 1; i < 6; i++) {
	document.write("<area shape=rect " + 
	"coords='" + starMap[i] + "' " +
	"onMouseOver=\"StarMouseOver('" + id + "'," + i + ");\" " +
	"onMouseOut=\"StarMouseOut('" + id + "');\" " +
	"onClick=\"SaveStars('" + id + "'," + i + ");" +
	"\" >");
	}
	document.write("</map>");
	document.write("<img vspace=2 title = 'Rate Picture' src='" + starImages[rating] + "'");
	document.write(" border=0 usemap='#starmap" + id);
	document.write("' id='" + starID + "'>");
}
function DisplayMsg (id, rating){
	var msgID = "messages." + id;
	if ( rating == undefined ) {
	document.write("<img vspace=2 height=11 src='" + nullStarMessage + "'");
	}
	else {
	document.write("<img vspace=2 height=11 src='" + starMessages[rating] + "'"); 
	}
	document.write("' id='" + msgID + "'>");
}