extension.js

(function() {
	if (document.URL.match(/beermenus\.com\/places/)) { 
		var trs = document.getElementsByTagName("tr");
		var minPpoz = null;
		for (var i = 0; i < trs.length; i++) {
			var tds = trs[i].children;
			var name = null;
			var serving = null;
			var abv = null;
			var price = null;
			var priceElem = null;
			for (var j = 0; j < tds.length; j++) {
				var td = tds[j];
				var clazz = td.getAttribute("class");
				if (clazz != null) {
					if (clazz == "serving") {
						serving = td.innerText;
					} else if (clazz == "abv") {
						abv = parseFloat(td.innerText);
					} else if (clazz == "price") {
						var parsePrice = td.innerText.match(/\d+\.\d+/);
						if (parsePrice) {
							price = parseFloat(parsePrice);
						}
						priceElem = td;
					}
				} else {
					if (td.children && td.children.length > 0 && td.children[0].tagName == "A") {
						name = td.children[0].innerText;
					}
				}
			}				
			if (name != null && serving != null && abv != null && ! isNaN(abv) && price != null) {
				var servingMatch = serving.match(/(\d+)oz\. ((\d+) Pack)?/);
				if (servingMatch) {
					var oz = servingMatch[1];
					var pack = 1;
					if (servingMatch[3]) {
						pack = parseInt(servingMatch[3]);						
					}
					var ppoz = price / (oz * pack *  abv * .01);
					var ppozDiv = document.createElement("div");
					ppozDiv.setAttribute("style", "color: blue");
					ppozDiv.innerText = "$" + ppoz.toFixed(2) + " ppoza";
					priceElem.appendChild(ppozDiv);
					if (minPpoz == null || minPpoz.price > ppoz) {
						minPpoz = { name: name, price: ppoz };
					}
				}
			}
		}
		if (minPpoz) {
			var p = document.getElementsByTagName("p");
			for (var i = 0; i < p.length; i++) {
				if (p[i].getAttribute("class") && p[i].getAttribute("class") == "left") {
					var ppozDiv = document.createElement("div");
					ppozDiv.setAttribute("style", "color: blue");
					ppozDiv.innerText = "Best value: " + minPpoz.name;
					p[i].appendChild(ppozDiv);
				}
			}
		}
	}
})();