Add Google Book cover art to a webpage.

gbs_covers.js

var DEBUG = false;
var MAXBUFFER = 10;

function debug_init() {
	this.debug_log = document.createElement("div");
	this.debug_log.id = 'debug';
 	this.debug_log.setAttribute('style', "min-height: 1em; width: 95%; border: 1px solid #FF6400; margin-left: auto; margin-right: auto;");
	h2 = document.createElement('h2');
	h2.setAttribute('style', "color: #fff; background-color: #FF6400; margin: 0 0 0.75em 0; height: 1.5em; font-size: 1.2em; padding: 5px 0 3px 0;");
	h2.innerHTML = 'DEBUG LOG';
	this.debug_log.appendChild(h2);
	
	document.body.appendChild(this.debug_log);
}
function debug_msg(sbj, msg) {
	if (DEBUG)
		this.debug_log.innerHTML += "<strong>"+sbj+":</strong> "+msg+"<br />";
}

// Define cross-platform CSS handlers
function Stylesheet(ss) {
	if (typeof ss == "number") ss = document.styleSheets[ss];
	this.ss = ss;
}
Stylesheet.prototype.getRules = function() {
	return this.ss.cssRules?this.ss.cssRules:this.ss.rules;
}
Stylesheet.prototype.getRule = function(s) {
	var rules = this.getRules();
	if (!rules) return null;
	if (typeof s == "number") return rules[s];
	s = s.toLowerCase();
	for(var i = rules.length-1; i >= 0; i--) {
		if (rules[i].selectorText.toLowerCase() == s) return rules[i];
	}
	return null;
};
Stylesheet.prototype.getStyles = function(s) {
	var rule = this.getRule(s);
	if (rule && rule.style) return rule.style;
	else return null;
};
Stylesheet.prototype.getStyleText = function(s) {
	var rule = this.getRule(s);
	if (rule && rule.style && rule.style.cssText) return rule.style.cssText;
	else return "";
};
Stylesheet.prototype.insertRule = function(selector, styles, n) {
	if (n == undefined) {
		var rules = this.getRules();
		n = rules.length;
	}
	if (this.ss.insertRule)	// Try the W3C API first
		this.ss.insertRule(selector + "{"+ styles +"}", n);
	else if (this.ss.addRule) // Otherwise, use the IE API
		this.ss.addRule(selector, styles, n);
}
Stylesheet.prototype.deleteRule = function(s) {
	// If s is undefined, make it the index of the last rule
	if (s == undefined) {
		var rules = this.getRules();
		s = rules.length-1;
	}
	
	// If s is not a number, look for a matching rule and get its index
	if (typeof s != "number") {
		s = s.toLowerCase();
		var rules = this.getRules();
		for(var i = rules.length-1; i >= 0; i--) {
			if (rules[i].selectortext.toLowerCase() == s) {
				s = i;
				break;
			}
		}
		if (i == -1) return;
	}
	if (this.ss.deleteRule) this.ss.deleteRule(s);
	else if (this.ss.removeRule) this.ss.removeRule(s);
}


function gbook_coverart(data) {
	for (i in data) {
		var book = data[i];
		if (book.thumbnail_url != undefined) {
			updateCover(book.bib_key.replace(':', '_'), book);
		}
	}
}
function gbookScript(bibkeys, callback) {
	var script = document.createElement("script");
	src = "http://books.google.com/books?jscmd=viewapi&bibkeys="+escape(bibkeys.join(','))+"&callback="+callback;
	debug_msg('SCRIPT', ' <a href="'+src+'">Google Books API call</a>');
	script.src = src;
	document.body.appendChild(script);
}
function updateCover(bibkey, book) {
	debug_msg('UPDATE COVER', bibkey+'<a href="'+book.thumbnail_url+'">thumbnail url</a>');
	gbook_div = document.getElementById(bibkey);
	if (gbook_div.className == 'gbookthumbnail' && book.thumbnail_url) {
		gbook_div.innerHTML =	'<img src="'+book.thumbnail_url+'" border="0" alt="" />';
	}	else if (gbook_div.className == 'gbookpreview' && book.preview_url) {
		link_text = 'More Info';
		if(book.preview == 'partial') { link_text = 'Preview'; }
		if(book.preview == 'full') { link_text = 'Full Text'; }
		gbook_div.innerHTML = 
				'<a href="'+book.preview_url+'" class="thumbnail" target="_blank">'
			+ '<img src="'+book.thumbnail_url+'" border="0" alt="" />'
			+ '<span style="padding-top: 3px; display: block;">' + link_text + '</span></a>';
	} else if (gbook_div.className == 'gbookfull') {
		
	}

}

window.onload = function() {
	if (DEBUG) { debug_init(); }
	
	// Refactor this
	ss = new Stylesheet(0);
	ss.insertRule(".gbookpreview", "width: 80px; text-align: center; padding: 0; margin: 0px;");
	ss.insertRule(".gbookpreview a", "margin: 0px; padding: 0px; color: darkblue; text-decoration: none; text-transform: uppercase; font-size: 10px; font-weight: bold;");
	ss.insertRule(".gbookpreview a:hover", "color: #000;");
	ss.insertRule(".gbookpreview img", "margin: 0px; padding: 0px;");

	allDivs = document.getElementsByTagName('div');
	bibkeys = [];
	for (i in allDivs) {
		var div = allDivs[i];
		if (div.className == 'gbookthumbnail' || div.className == 'gbookpreview' || div.className == 'gbsthumbnail') {
			var bibkey = div.getAttribute('bibkey').split(' ')[0];
			bibkeys.push(bibkey);
			div.setAttribute('id', bibkey.replace(':', '_'));
			div.innerHTML =	'<img src="/images/cover.png" height="80" border="0" alt="" />';
			debug_msg('GET COVER', bibkey);
		}
		if (bibkeys.length >= MAXBUFFER) {
			gbookScript(bibkeys, 'gbook_coverart');
			bibkeys = [];
		}
	}
	if (bibkeys.length > 0) {
		gbookScript(bibkeys, 'gbook_coverart');
	}
}