

方法一、利用CSS3.0样式新特性实现北京全屏 (不支持ie6-8)
html {
background: url(images/bg.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}或:
html{
background:url('background.jpg') no-repeat center center;
min-height:100%;
background-size:cover;
}
body{
min-height:100%;
}原理:将html及body设置为最小高度为100%,使用css3中的background-size:cover;将背景图片设置成封面全屏模式。
兼容性:
Safari 3+
Chrome Whatever+
IE 9+
Opera 10+
Firefox 3.6+
方法二、使用jQuery实现
HTML代码:
<img src="images/bg.jpg" id="bg" alt="">
CSS代码:
#bg { position: fixed; top: 0; left: 0; }
.bgwidth { width: 100%; }
.bgheight { height: 100%; }jQuery代码:
$(window).load(function() {
var theWindow = $(window),
$bg = $("#bg"),
aspectRatio = $bg.width() / $bg.height();
function resizeBg() {
if ( (theWindow.width() / theWindow.height()) < aspectRatio ) {
$bg
.removeClass()
.addClass('bgheight');
} else {
$bg
.removeClass()
.addClass('bgwidth');
}
}
theWindow.resize(resizeBg).trigger("resize");
});兼容性:
IE7+
任何桌面浏览器
方法二、使用jQuery实现(附)【使用jQuery插件jQuery.fullBg】
First comes the plugin code:
/**
* jQuery.fullBg
* Version 1.0
* Copyright (c) 2010 c.bavota - http://bavotasan.com
* Dual licensed under MIT and GPL.
* Date: 02/23/2010
**/
(function($) {
$.fn.fullBg = function(){
var bgImg = $(this);
function resizeImg() {
var imgwidth = bgImg.width();
var imgheight = bgImg.height();
var winwidth = $(window).width();
var winheight = $(window).height();
var widthratio = winwidth / imgwidth;
var heightratio = winheight / imgheight;
var widthdiff = heightratio * imgwidth;
var heightdiff = widthratio * imgheight;
if(heightdiff>winheight) {
bgImg.css({
width: winwidth+'px',
height: heightdiff+'px'
});
} else {
bgImg.css({
width: widthdiff+'px',
height: winheight+'px'
});
}
}
resizeImg();
$(window).resize(function() {
resizeImg();
});
};
})(jQuery)There is only a little CSS needed for this one:
.fullBg {
position: absolute;
top: 0;
left: 0;
overflow: hidden;
}
#maincontent {
position: absolute;
top: 0;
left: 0;
z-index: 50;
}If you want your background to stay fixed you can change the .fullBG CSS to this:
.fullBg {
position: fixed;
top: 0;
left: 0;
overflow: hidden;
}For the HTML markup, you can just add an image tag with an id or class, but you also need to add a div that contains your main content or else it won’t work properly. This is the bare minimum:
<img src="your-background-image.jpg" alt="" id="background" /> <div id="maincontent"> <!-- Your site content goes here --> </div>
To call the jQuery function, add this to the bottom of your web page, right before the closing body tag:
<script type="text/javascript">
$(window).load(function() {
$("#background").fullBg();
});
</script>Once again, this plugin is pretty simple so no options are available. It pretty much just does what it does.
