实现网页背景图片拉伸的两种方法

body{background:url(bg.jpg) center center;background-size:cover;height:900px;width:100%;
filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(src='bg.jpg', sizingMethod='scale');}

$(function(){
$("body").append("<div id='main_bg' style="position:absolute;"/>");
$("#main_bg").append("<img src='bg.jpg' id='bigpic'>");
cover();
$(window).resize(function(){ //浏览器窗口变化
cover();
});
});
function cover(){
var win_width = $(window).width();
var win_height = $(window).height();
$("#bigpic").attr({width:win_width,height:win_height});
}