/*查看大圖*/
var screenheight = $(window).height();
var screenwidth = $(window).width();
var loadCSS = function(){
var screenwidth = $(window).width();
var screenheight = $(window).height();
$("div.lookBigPicture").css({"left":screenwidth*0.2,"top":screenheight*0.15+$(document).scrollTop(),
"width":screenwidth*0.6,"height":screenheight*0.7});
$("img.bigImg").css({"max-width":(screenwidth*0.6 - 30),"max-height":screenheight*0.7-40});
$("img.bigImg").load(function(){
$("img.bigImg").css("top",(screenheight*0.7 - 30 - $("img.bigImg").height())*0.5 + 30);
});
$("img.bigImg").css("top",(screenheight*0.7 - 30 - $("img.bigImg").height())*0.5 + 30);
$.log("$(document).height():"+$(document).height());
};
$("a#bigPic").click(function(){
$.log("screenheight:"+screenheight+"screenwidth:"+screenwidth);
str = $("img[img-size]").attr("src");
$("body").append("<div class='grey'></div>");//灰色底層
$("body").append("<div class='lookBigPicture'><span class='protoPic'><a z-index='20001' target='_blank' href='"+str+"'>查看原圖</a></span><a href='javascript:;' class='bigpicclose' title='關閉'>×</a><img class='bigImg' src='"+str+"'/></div>");
$("div.grey").css( "height",$(document).height());
loadCSS();
$("body").css({overflow:"hidden"}); //禁用滾動條
});
$("body").delegate("div.grey,a.bigpicclose","click",function(){
$("body").css({overflow:"visible"}); //恢復滾動條
$("div.lookBigPicture").remove();
$("div.grey").remove();
});
//當瀏覽器窗口大小改變時
$(window).resize(function () {
loadCSS();
});

/***遮罩層****/
.grey {
background: #000;
display: block;
z-index: 1000;
width: 100%;
position: absolute;
filter: alpha(opacity : 50);
opacity: 0.5;
top: 0;
left: 0;
top: 0;
}

.lookBigPicture {
border: #000 solid 1px;
position: absolute;
z-index: 2000;
text-align: center;
background: black;
}

.bigImg {
margin-left: auto;
margin-right: auto;
position: relative;
}

.bigpicclose {
position: absolute;
width: 36px;
height: 36px;
font-size: 0;
z-index: 20001;
top: -18px;
right: -18px;
background:
url("http://img.t.sinajs.cn/t5/style/images/layer/multipic_ico.png?id=20131018174500")
0 0 no-repeat;
}

.lookbigicn {
display: inline-block;
width: 12px;
height: 12px;
background:
url("http://img.t.sinajs.cn/t5/style/images/common/icon.png?id=1383027536816")
-175px -25px no-repeat;
vertical-align: -2px;
margin-left: 20px;
}

.W_ico12 {
display: inline-block;
width: 12px;
height: 12px;
background:
url("http://img.t.sinajs.cn/t5/style/images/common/icon.png?id=1383027536816")
-175px 0px no-repeat;
vertical-align: -2px;
}

.protoPic {
position: absolute;
display: inline-block;
height: 30px;
top: 10px;
right: 50px;
overflow: hidden;
cursor: pointer;
color: #F8F8F8;
text-shadow: 0 1px 0 rgba(0, 0, 0, .5);
}

<p pic-choice style="display: none;">
<em class="W_ico12"></em><a href="javascript:;" id="hidePic">收起</a>
<em class="lookbigicn"></em><a href="javascript:;" id="bigPic">查看大圖</a>
</p>