Front-end learning the seventh bullet: JavaScript implements lazy loading of pictures

Front-end learning the seventh bullet: JavaScript implements lazy loading of pictures

In order to achieve the picture into the field of view before starting to load first:

At this point src is empty without loading the picture

$ (window). Scroll (function  () {    $ ("img"). each (function() {        if ($ (this). src = = "")           {if ((). Offset (). Top + $ (this). Width ()/2) < ($ (window). Height () +$ (window). scrolltop ()) {            $ (this). attr ("src", $ (This ). attr ("X-src"))         ;}});

$ (). attr (,) sets and returns a property of an element

Front-end learning the seventh bullet: JavaScript implements lazy loading of pictures