图片懒加载怎么写？

放进去里就可以了

 //图片懒加载
    var imgLazy;
    (function () {
        var imgList = [],  // 页面所有img元素集合
                delay,   // setTimeout 对象
                offset,  //偏移量，用于指定图片距离可视区域多少距离，进行加载
                time,  // 延迟载入时间
                _selector; // 选择器 默认为 .m-lazyload

        function _isShow(el) {
            var coords = el.getBoundingClientRect();
            return ( (coords.top >= 0 && coords.left >= 0 && coords.top) <= (window.innerHeight || document.documentElement.clientHeight) + parseInt(offset));
        }

        function _loadImage() {

            for (var j = imgList.length; j--;) {
                var el = imgList[j];
                if (_isShow(el)) {
                    el.src = el.getAttribute('data-src');
                    el.removeAttribute('data-src');
                    $('img').removeClass('m-lazyload');
                    imgList.splice(j, 1);
                }
            }
        }

        function _delay() {
            clearTimeout(delay);
            delay = setTimeout(function () {
                _loadImage();
            }, time);
        }

        imgLazy = function ImageLazyload(selector, options) {
            var defaults = options || {};
            offset = defaults.offset || 0;
            time = defaults.time || 250;
            _selector = selector || '.m-lazyload';
            this.getNode();
            _delay();//避免首次加载未触发touch事件,主动触发一次加载函数
            if (defaults.iScroll) {
                defaults.iScroll.on('scroll', _delay);
                defaults.iScroll.on('scrollEnd', _delay);
            } else {
                window.addEventListener('scroll', _delay, false);
            }
        }
        imgLazy.prototype.getNode = function () {
            imgList = [];
            var nodes = document.querySelectorAll(_selector);
            for (var i = 0, l = nodes.length; i < l; i++) {
                imgList.push(nodes[i]);
            }

        };

    })();
    var lazyload = new imgLazy('.m-lazyload',{
        delay: 100,   // setTimeout 对象
        offset: 500,  //图片距离可视区域多少距离
        time :100  // 延迟载入时间
    });