<code>
(function(a) {
    a.backstretch = function(k, i, l) {
        function m(c) {
            try {
                f = {
                    left: 0,
                    top: 0
                };
                d = e.width();
                b = d / j;
                if (b >= e.height()) {
                    g = (b - e.height()) / 2;
                    h.centeredY && a.extend(f, {
                        top: "-" + g + "px"
                    })
                } else {
                    b = e.height();
                    d = b * j;
                    g = (d - e.width()) / 2;
                    h.centeredX && a.extend(f, {
                        left: "-" + g + "px"
                    })
                }
                a("#backstretch img").width(d).height(b).css(f)
            } catch(n) {}
            typeof c == "function" && c()
        }
        var h = {
            centeredX: true,
            centeredY: true,
            speed: 0
        },
        e = "onorientationchange" in window ? a(document) : a(window),
        j,
        d,
        b,
        g,
        f;
        i && typeof i == "object" && a.extend(h, i);
        a(document).ready(function() {
            if (k) {
                var c = a("<div />").attr("id", "backstretch").css({
                    left: 0,
                    top: 0,
                    position: "fixed",
                    overflow: "hidden",
                    zIndex: -9999
                }),
                n = a("<img />").css({
                    position: "relative",
                    display: "none"
                }).bind("load",
                function(o) {
                    var p = a(this);
                    j = a(o.target).width() / a(o.target).height();
                    m(function() {
                        p.fadeIn(h.speed,
                        function() {
                            typeof l == "function" && l()
                        })
                    })
                }).appendTo(c);
                a("body").prepend(c);
                n.attr("src", k);
                a(window).resize(m)
            }
        });
        return this
    }
})(jQuery);
</code>

<code>
$.backstretch("http://xxxxxxx/1.jpg", {speed: 850});
</code>

<code>
//定义一个数组，储存图片路径
    var images = [
        "http://xxxx/images/bg/1.jpg",
        "http://xxxx/images/bg/2.jpg",
        "http://xxxx/images/bg/3.jpg",
        "http://xxxx/4.jpg",
        "http://xxxx/5.jpg"
    ];
///遍历数组 创建一个循环
    $(images).each(function(){
       $('<img/>')[0].src = this; 
    });
    var index = 0;
//调用backstretch函数，并且设定速度为2000毫秒，淡入淡出效果
    $.backstretch(images[index], {speed: 2000});
//创建计时器
    setInterval(function() {
        index = (index >= images.length - 1) ? 0 : index + 1;
        $.backstretch(images[index]);
    }, 20000);
</code>

<code>
/*! Backstretch - v2.0.3 - 2012-11-30
* http://srobbin.com/jquery-plugins/backstretch/
* Copyright (c) 2012 Scott Robbin; Licensed MIT */
(function(e,t,n){"use strict";e.fn.backstretch=function(r,s){return(r===n||r.length===0)&&e.error("No images were supplied for Backstretch"),e(t).scrollTop()===0&&t.scrollTo(0,0),this.each(function(){var t=e(this),n=t.data("backstretch");n&&(s=e.extend(n.options,s),n.destroy(!0)),n=new i(this,r,s),t.data("backstretch",n)})},e.backstretch=function(t,n){return e("body").backstretch(t,n).data("backstretch")},e.expr[":"].backstretch=function(t){return e(t).data("backstretch")!==n},e.fn.backstretch.defaults={centeredX:!0,centeredY:!0,duration:5e3,fade:0};var r={wrap:{left:0,top:0,overflow:"hidden",margin:0,padding:0,height:"100%",width:"100%",zIndex:-999999},img:{position:"absolute",display:"none",margin:0,padding:0,border:"none",width:"auto",height:"auto",maxWidth:"none",zIndex:-999999}},i=function(n,i,o){this.options=e.extend({},e.fn.backstretch.defaults,o||{}),this.images=e.isArray(i)?i:[i],e.each(this.images,function(){e("<img />")[0].src=this}),this.isBody=n===document.body,this.$container=e(n),this.$wrap=e('<div class="backstretch"></div>').css(r.wrap).appendTo(this.$container),this.$root=this.isBody?s?e(t):e(document):this.$container;if(!this.isBody){var u=this.$container.css("position"),a=this.$container.css("zIndex");this.$container.css({position:u==="static"?"relative":u,zIndex:a==="auto"?0:a,background:"none"}),this.$wrap.css({zIndex:-999998})}this.$wrap.css({position:this.isBody&&s?"fixed":"absolute"}),this.index=0,this.show(this.index),e(t).on("resize.backstretch",e.proxy(this.resize,this)).on("orientationchange.backstretch",e.proxy(function(){this.isBody&&t.pageYOffset===0&&(t.scrollTo(0,1),this.resize())},this))};i.prototype={resize:function(){try{var e={left:0,top:0},n=this.isBody?this.$root.width():this.$root.innerWidth(),r=n,i=this.isBody?t.innerHeight?t.innerHeight:this.$root.height():this.$root.innerHeight(),s=r/this.$img.data("ratio"),o;s>=i?(o=(s-i)/2,this.options.centeredY&&(e.top="-"+o+"px")):(s=i,r=s*this.$img.data("ratio"),o=(r-n)/2,this.options.centeredX&&(e.left="-"+o+"px")),this.$wrap.css({width:n,height:i}).find("img:not(.deleteable)").css({width:r,height:s}).css(e)}catch(u){}return this},show:function(t){if(Math.abs(t)>this.images.length-1)return;this.index=t;var n=this,i=n.$wrap.find("img").addClass("deleteable"),s=e.Event("backstretch.show",{relatedTarget:n.$container[0]});return clearInterval(n.interval),n.$img=e("<img />").css(r.img).bind("load",function(t){var r=this.width||e(t.target).width(),o=this.height||e(t.target).height();e(this).data("ratio",r/o),e(this).fadeIn(n.options.speed||n.options.fade,function(){i.remove(),n.paused||n.cycle(),n.$container.trigger(s,n)}),n.resize()}).appendTo(n.$wrap),n.$img.attr("src",n.images[t]),n},next:function(){return this.show(this.index<this.images.length-1?this.index+1:0)},prev:function(){return this.show(this.index===0?this.images.length-1:this.index-1)},pause:function(){return this.paused=!0,this},resume:function(){return this.paused=!1,this.next(),this},cycle:function(){return this.images.length>1&&(clearInterval(this.interval),this.interval=setInterval(e.proxy(function(){this.paused||this.next()},this),this.options.duration)),this},destroy:function(n){e(t).off("resize.backstretch orientationchange.backstretch"),clearInterval(this.interval),n||this.$wrap.remove(),this.$container.removeData("backstretch")}};var s=function(){var e=navigator.userAgent,n=navigator.platform,r=e.match(/AppleWebKit\/([0-9]+)/),i=!!r&&r[1],s=e.match(/Fennec\/([0-9]+)/),o=!!s&&s[1],u=e.match(/Opera Mobi\/([0-9]+)/),a=!!u&&u[1],f=e.match(/MSIE ([0-9]+)/),l=!!f&&f[1];return!((n.indexOf("iPhone")>-1||n.indexOf("iPad")>-1||n.indexOf("iPod")>-1)&&i&&i<534||t.operamini&&{}.toString.call(t.operamini)==="[object OperaMini]"||u&&a<7458||e.indexOf("Android")>-1&&i&&i<533||o&&o<6||"palmGetResource"in t&&i&&i<534||e.indexOf("MeeGo")>-1&&e.indexOf("NokiaBrowser/8.5.0")>-1||l&&l<=6)}()})(jQuery,window);</code>

<code> $.backstretch("http://xxx/garfield-interior.jpg");</code>

<code>jQuery(document).ready(function ($) {
/*背景*/
    $.backstretch(bgimg, {fade: 3000, duration: 7000});
});</code>

<code>
    var bgimg = [ "http://xxx/0.jpg",
      "http://xxx/1.jpg",
       "http://xxx/2.jpg",
        "http://xxx/3.jpg",
         "http://xxx/4.jpg",
          "http://xxx/5.jpg",
           "http://xxx/6.jpg",
            "http://xxx/7.jpg",
             "http://xxx/8.jpg",
              "http://xxx/9.jpg",
               "http://xxx/10.jpg",
                "http://xxx/11.jpg",
                 "http:/xxx/12.jpg"
      ];
      bgimg.sort(function(){return Math.random()>0.5?-1:1;});
/***代码源自http://winysky.com/，表示感谢~~***/</code>

<code>/*
 * At its core, Backstretch is a one-line plugin.
 * Just pass in the path to an image, and you're done.
 */
 
  $.backstretch("http://dl.dropbox.com/u/515046/www/garfield-interior.jpg");
</code>

<code>/*
 * Here is an example of how to use Backstretch as a slideshow.
 * Just pass in an array of images, and optionally a duration and fade value.
 */
 
  // Duration is the amount of time in between slides,
  // and fade is value that determines how quickly the next image will fade in
  $.backstretch([
      "http://dl.dropbox.com/u/515046/www/outside.jpg"
    , "http://dl.dropbox.com/u/515046/www/garfield-interior.jpg"
    , "http://dl.dropbox.com/u/515046/www/cheers.jpg"
  ], {duration: 3000, fade: 750});</code>

<code>/*
 * You can easily attach Backstretch to jQuery events, like click
 * 
 * Click the buttons above to see the background image change
 */
 
  $("#outside").click(function(e) {
    e.preventDefault();
    $.backstretch('http://dl.dropbox.com/u/515046/www/outside.jpg');
  });
 
  $("#cheers").click(function(e) {
    e.preventDefault();
    $.backstretch('http://dl.dropbox.com/u/515046/www/cheers.jpg');
  });</code>

<code>/*
 * If you'd like, you can attach Backstretch to any block-level element. 
 * For example, this demo.
 */
 
  $("#demo").backstretch("http://dl.dropbox.com/u/515046/www/garfield-interior.jpg");
</code>