(function (w) {
	"use strict";
	// rel=preload support test
	if (!w.loadCSS) {
		w.loadCSS = function () {
		};
	}
	// define on the loadCSS obj
	var rp = loadCSS.relpreload = {};
	// rel=preload feature support test
	// runs once and returns a function for compat purposes
	rp.support = (function () {
		var ret;
		try {
			ret = w.document.createElement("link").relList.supports("preload");
		} catch (e) {
			ret = false;
		}
		return function () {
			return ret;
		};
	})();

	// if preload isn't supported, get an asynchronous load by using a non-matching media attribute
	// then change that media back to its intended value on load
	rp.bindMediaToggle = function (link) {
		// remember existing media attr for ultimate state, or default to 'all'
		var finalMedia = link.media || "all";

		function enableStylesheet() {
			link.media = finalMedia;
		}

		// bind load handlers to enable media
		if (link.addEventListener) {
			link.addEventListener("load", enableStylesheet);
		} else if (link.attachEvent) {
			link.attachEvent("onload", enableStylesheet);
		}

		// Set rel and non-applicable media type to start an async request
		// note: timeout allows this to happen async to let rendering continue in IE
		setTimeout(function () {
			link.rel = "stylesheet";
			link.media = "only x";
		});
		// also enable media after 3 seconds,
		// which will catch very old browsers (android 2.x, old firefox) that don't support onload on link
		setTimeout(enableStylesheet, 3000);
	};

	// loop through link elements in DOM
	rp.poly = function () {
		// double check this to prevent external calls from running
		if (rp.support()) {
			return;
		}
		var links = w.document.getElementsByTagName("link");
		for (var i = 0; i < links.length; i++) {
			var link = links[i];
			// qualify links to those with rel=preload and as=style attrs
			if (link.rel === "preload" && link.getAttribute("as") === "style" && !link.getAttribute("data-loadcss")) {
				// prevent rerunning on link
				link.setAttribute("data-loadcss", true);
				// bind listeners to toggle media back
				rp.bindMediaToggle(link);
			}
		}
	};

	// if unsupported, run the polyfill
	if (!rp.support()) {
		// run once at least
		rp.poly();

		// rerun poly on an interval until onload
		var run = w.setInterval(rp.poly, 500);
		if (w.addEventListener) {
			w.addEventListener("load", function () {
				rp.poly();
				w.clearInterval(run);
			});
		} else if (w.attachEvent) {
			w.attachEvent("onload", function () {
				rp.poly();
				w.clearInterval(run);
			});
		}
	}


	// commonjs
	if (typeof exports !== "undefined") {
		exports.loadCSS = loadCSS;
	}
	else {
		w.loadCSS = loadCSS;
	}
}(typeof global !== "undefined" ? global : this));