forked from qwerty/tupali
57 lines
1.3 KiB
JavaScript
57 lines
1.3 KiB
JavaScript
/**
|
|
* jQuery Unveil
|
|
* A very lightweight jQuery plugin to lazy load images
|
|
* http://luis-almeida.github.com/unveil
|
|
*
|
|
* Licensed under the MIT license.
|
|
* Copyright 2013 Luís Almeida
|
|
* https://github.com/luis-almeida
|
|
*/
|
|
|
|
;(function($) {
|
|
|
|
$.fn.unveil = function(threshold, callback) {
|
|
|
|
var $w = $(window),
|
|
th = threshold || 0,
|
|
retina = window.devicePixelRatio > 1,
|
|
attrib = retina? "data-src-retina" : "data-src",
|
|
images = this,
|
|
loaded;
|
|
|
|
this.one("unveil", function() {
|
|
var source = this.getAttribute(attrib);
|
|
source = source || this.getAttribute("data-src");
|
|
if (source) {
|
|
this.setAttribute("src", source);
|
|
if (typeof callback === "function") callback.call(this);
|
|
}
|
|
});
|
|
|
|
function unveil() {
|
|
var inview = images.filter(function() {
|
|
var $e = $(this);
|
|
if ($e.is(":hidden")) return;
|
|
|
|
var wt = $w.scrollTop(),
|
|
wb = wt + $w.height(),
|
|
et = $e.offset().top,
|
|
eb = et + $e.height();
|
|
|
|
return eb >= wt - th && et <= wb + th;
|
|
});
|
|
|
|
loaded = inview.trigger("unveil");
|
|
images = images.not(loaded);
|
|
}
|
|
|
|
$w.on("scroll.unveil resize.unveil lookup.unveil", unveil);
|
|
|
|
unveil();
|
|
|
|
return this;
|
|
|
|
};
|
|
|
|
})(window.jQuery || window.Zepto);
|