User:Irukaza/common.css

window.smallDelay = (function(window, document, undefined) {
    'use strict';
    var store = [],poll;
    var settings = {
        offset:0, //离可视区域多少像素的图片可以被加载
        throttle: 250 //图片延时多少毫秒加载
    }
        
    var _inView = function(el) {
        var coords = el.getBoundingClientRect();
        return ((coords.top >= 0 && coords.left >= 0) && coords.top <= ((window.innerHeight || document.documentElement.clientHeight) + parseInt(settings.offset)));
    };

    var _pollImages = function() {
        for (var i = store.length; i--;) {
            var self = store[i];
            if (_inView(self)) {
                self.src = self.getAttribute('data-delay');
                store.splice(i, 1);
            }
        }
    };

    var _throttle = function() {
        clearTimeout(poll);
        poll = setTimeout(_pollImages, settings.throttle);
    };

    var init = function(obj) {
        var nodes = document.querySelectorAll('[data-delay]');
        var opts = obj || {};
        settings.offset = opts.offset || settings.offset;
        settings.throttle = opts.throttle || settings.throttle;

        for (var i = 0; i < nodes.length; i++) {
            store.push(nodes[i]);
        }

        _throttle();
        
        //滚动监听执行图片懒加载
        if (document.addEventListener) {
            window.addEventListener('scroll', _throttle, false);
        } else {
            window.attachEvent('onscroll', _throttle);
        }
        
        //返回该对象进行链式操作
        return this;
    };

    return {
        init: init,
        render: _throttle
    };

})(window, document);