General ideas and examples of js image delay technology_javascript skills

General ideas of image delay technology

1. Now set the src path corresponding to the img element as the background image, and the url path corresponding to the img is stored in a self-set attribute (for src replacement).

2. Get the height of the scroll and the height of the window

3 Loop through the img array that needs to be delayed loaded, get the height of the img, and determine whether the element is within the visual window. If the element is within the visual window, replace src

with the test code

html

Copy code The code is as follows:

< ;li>

< ;li>

js part

Copy code The code is as follows:

var imgsglobal=[
"http://cdn.duitang.com/uploads/item/201306/07/20130607171626_QkC3T.thumb.600_0.jpeg",
"http://img4.duitang.com/uploads/item/201306/07/20130607172438_Teijr.jpeg",
"http://cdn.duitang.com/uploads/item/201306/08/20130608190311_BYwcA.thumb.600_0.jpeg",
"http://g-ec4.images-amazon.com/images/G/28/BOOK-Catalog/Liaoxiaojun/B003U5TATY_01_AMZN.jpg",
"http://www.yishun.net/tuysL3R1eXNpbWcwNC50YW9iYW9jZG4uY29tL2ltZ2V4dHJhL2k0Lzc0MDY1MDAzMi9UMl9HbmVYanRhWFhYWFhYWFhfISE3NDA2NTAwMzIuanBn.jpg",
"http://www.yishun.net/tuysL3R1eXNpbWcwMy50YW9iYW9jZG4uY29tL2ltZ2V4dHJhL2kzLzc0MDY1MDAzMi9UMkVHbF9YaVhjWFhYWFhYWFhfISE3NDA2NTAwMzIuanBn.jpg",
"http://img4.duitang.com/uploads/item/201306/08/20130608190125_3kFty.jpeg",
"http://img4.duitang.com/uploads/item/201304/29/20130429142901_SQjJv.thumb.600_0.jpeg",
"http://img4.duitang.com/uploads/item/201112/04/20111204170801_fiBKm.jpg",
"http://img2.duitang.com/uploads/item/201211/06/20121106233027_LdQaS.thumb.600_0.jpeg",
"http://i2.sinaimg.cn/gm/2011/0127/U5238P115DT20110127111837.jpg",
"http://img2.duitang.com/uploads/item/201209/24/20120924162953_hLPJe.jpeg",
"http://wenwen.soso.com/p/20110624/20110624085901-745594320.jpg",
"http://img4.duitang.com/uploads/item/201206/15/20120615185646_uzmrt.thumb.600_0.jpeg",
"http://img4.duitang.com/uploads/item/201202/11/20120211213039_U4Sj8.thumb.600_0.jpg",
"http://cdn.duitang.com/uploads/item/201201/25/20120125145922_n4Vz8.thumb.600_0.jpg"
];
function addImgEle(){
var str='';
for(var i=0, len=imgsglobal.length; istr ='

'
}
$("#showImg").append(str);
}
$(document).ready(function(){
addImgEle();
});
(function(win){
var lazyLoad=win['lazyLoad']||{};
var camelize = function (s) {
return s.replace(/-(w)/g, function (strMatch, p1) {
return p1.toUpperCase();
});
};
lazyLoad={
init:function(ImgClass){
var offsetPage = window.pageYOffset ? window.pageYOffset : window.document.documentElement.scrollTop,
offsetWindow = offsetPage Number(window.innerHeight ? window.innerHeight : document.documentElement.clientHeight);
var Imgeles=ImgClass;
for(var i=0, len=Imgeles.length; iif(Imgeles[i].getAttribute("resrc")=="show"){
continue;
}
var o=Imgeles[i];
if(o){
postPage = o.getBoundingClientRect().top window.document.documentElement.scrollTop window.document.body.scrollTop;
postWindow = postPage Number(this.getStyle(o, 'height').replace('px', ''));
if ((postPage > offsetPage && postPage < offsetWindow) || (postWindow > offsetPage && postWindow < offsetWindow)){
var src=o.getAttribute("resrc");
o.setAttribute("src", src);
o.setAttribute("resrc", "show");
}
}
}
},
getStyle:function (element, property) {
if (arguments.length != 2) return false;
var value = element.style[camelize(property)];
if (!value) {
if (document.defaultView && document.defaultView.getComputedStyle) {
var css = document.defaultView.getComputedStyle(element, null);
value = css ? css.getPropertyValue(property) : null;
} else if (element.currentStyle) {
value = element.currentStyle[camelize(property)];
}
}
return value == 'auto' ? '' : value;
}
}
win.lazyLoad=lazyLoad;
})(window);
$(document).ready(function(){
lazyLoad.init($("img.lazyImg"));
window.onscroll=function (){
lazyLoad.init($("img.lazyImg"));
}
});