jq--图片懒加载

html

1.给图片不给真真意义上的src属性路径，可通过我们自己想要添加时改变它的属性路径即可。

2.要获取浏览器中三种高度。

$(window).height();//屏幕高度
$(window).scrollTop();//滚动条距离顶部的高度
obj.offset().top;//元素距离顶部的高度

3.计算方法：img距离顶部的距离小于屏幕的高度加滚动条距顶部高度时加载图片，给图片设置真真的src属性的路径。

            <i class="displayB tea_proDetailPic"><img class="mI_img1" src="img/tea/tea_proDetail1.png" alt=""></i>
            <i class="displayB tea_proDetailPic"><img class="mI_img1" src="img/tea/tea_proDetail2.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_picTop"><img class="mI_img1" src="img/tea/tea_proDetail3.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_changePic"><img class="mI_img1" src="img/tea/tea_proDetail4.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_changePic"><img class="mI_img1" src="img/tea/tea_proDetail5.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_changePic"><img class="mI_img1" src="img/tea/tea_proDetail6.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_changePic"><img class="mI_img1" _src="img/tea/tea_proDetail7.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_changePic"><img class="mI_img1" _src="img/tea/tea_proDetail8.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_changePic"><img class="mI_img1" _src="img/tea/tea_proDetail9.png" alt=""></i>
            <i class="displayB tea_proDetailPic tea_changePic"><img class="mI_img1" _src="img/tea/tea_proDetail10.png" alt=""></i>
            <i class="displayB tea_proDetailPic"><img class="mI_img1" _src="img/tea/tea_proDetail11.png" alt=""></i>
            <i class="displayB tea_proDetailPic"><img class="mI_img1" _src="img/tea/tea_proDetail12.png" alt=""></i>
            <i class="displayB tea_proDetailPic"><img class="mI_img1" _src="img/tea/tea_proDetail13.png" alt=""></i>
            <i class="displayB tea_proDetailPic"><img class="mI_img1" _src="img/tea/tea_proDetail14.png" alt=""></i>
            <i class="displayB tea_proDetailPic"><img class="mI_img1" _src="img/tea/tea_proDetail15.png" alt=""></i>

jq

    ~(function() {
        var teaPic = $(".mI_img1");
        var wH = $(window).height();//屏幕高度
        teaPic.each(function(index,elem) {
            $(window).scroll(function() {
                var sTH = $(window).scrollTop();//滚动条距离顶部的距离
                if( $(".tea_proNav").offset().top < (wH + sTH)- 260 && $(elem).attr("_src") ) {
				    $(elem).attr('src',$(elem).attr('_src'));
			    }
            });
        });
    })();