仿QQ空间相册图片弹出效果

function imageShow(which_click) {
  var image_path = which_click.src;
  //alert(image_path);
  var tag_top = Math.max(document.documentElement.scrollTop, document.body.scrollTop);
  
  //创建底层灰色DIV
  var index_tag = document.createElement("div");
  index_tag.style.cssText = "width:100%;height:"+Math.max(document.body.clientHeight,document.body.offsetHeight,document.documentElement.clientHeight)+"px;position:absolute;background:black;top:0;filter: Alpha(Opacity=80);Opacity:0.8;";
  document.body.appendChild(index_tag);
  index_tag.ondblclick = closeIndexTag;
  
  //创建图片DIV
  var img_tag = document.createElement("div");
  img_tag.style.cssText = "font:12px /18px verdana;overflow:auto;text-align:center;position:absolute;width:200px;border:5px solid white;background:white;color:white;left:"+(parseInt(document.body.offsetWidth)/2-100)+"px;top:"+(document.documentElement.clientHeight/3+tag_top)+"px;";
  img_tag.innerHTML = "<div style='padding:10px;background:#cccccc;border:1px solid white'><img src='images/loading.gif' /><br /><br /><b style='color:#999999;font-weight:normal'>Image loading...</b><br /></div>";
  img_tag.oncontextmenu = function() {
   var clsOK=confirm("是否确定关闭图片显示");
   if(clsOK)
    closeIndexTag();
   return false;
  }
  img_tag.onmousemove = barDidplay;
  document.body.appendChild(img_tag);
  
  //构建图片关闭按钮
  var close_tag = document.createElement("div");
  close_tag.style.cssText = "display:none;position:absolute;left:10px;top:10px;color:black;";
  close_tag.innerHTML = "<b style='background:red;border:1px solid white;filter:Alpha(Opacity=50);Opacity:0.5;cursor:pointer;'>&nbsp;关闭&nbsp;</b>";
  close_tag.onclick = closeIndexTag;
  
  var img = new Image();
  img.src = image_path;
  img.style.cssText = "border:1px solid #cccccc;filter: Alpha(Opacity=0);Opacity:0;cursor:pointer";
  img.onload = imgOK();
  
  function imgOK() {
   var temp = 0;
   
   var stop_x = false;
   var stop_y = false;
   var img_tag_x = img_tag.offsetWidth;
   var img_tag_y = img_tag.offsetHeight;
   var img_x = img.width;
   var img_y = img.height;
   var scroll_x=document.documentElement.clientWidth;
   var scroll_y=window.innerHeight||document.documentElement.clientHeight;
   var yy = 0;
   var xx = 0;
   if(img_y > scroll_y || img_x > scroll_x){
    yy = scroll_y - 100;
    xx = (img_x / img_y) * yy;
   }else{
    xx = img_x + 4;
    yy = img_y + 3;
   }
   img.style.width=xx-4+'px';
   img.style.height=yy-3+'px';
   
   var maxTime = setInterval(function() {
    temp += 30;
    if((img_tag_x + temp) < xx) {
     img_tag.style.width = (img_tag_x + temp) + "px";
     img_tag.style.left = (scroll_x - img_tag_x - temp)/2 + "px";
    } else {
     stop_x = true;
     img_tag.style.width = xx + "px";
     img_tag.style.left = (scroll_x - xx)/2 + "px";
    }
    if((img_tag_y + temp) < yy) {
     img_tag.style.height = (img_tag_y + temp) + "px";
     img_tag.style.top = (tag_top + (scroll_y - img_tag_y - temp)/2) + "px";
    } else {
     stop_y = true;
     img_tag.style.height = yy + "px";
     img_tag.style.top = (tag_top + (scroll_y - yy)/2) + "px";
    }
    if(stop_x && stop_y) {
     clearInterval(maxTime);
     img_tag.appendChild(img);
     temp = 0;
     imgOpacity(temp);
    }
   }, 1);
   img_tag.innerHTML="";
   img_tag.appendChild(close_tag);
  }  
  
  function closeIndexTag() {
   document.body.removeChild(index_tag);
   document.body.removeChild(img_tag);
  }
  
  function imgOpacity(temp_imgOpacity) {
     var temp = temp_imgOpacity;
     temp += 10;
     img.style.filter = "alpha(opacity=" + temp + ")";
     img.style.opacity = temp/100;
     var imgTime = setTimeout(function() {imgOpacity(temp);}, 10);
     if(temp > 100)
      clearTimeout(imgTime);
  }
  
  var bar_show;
  function barDidplay(){
   clearTimeout(bar_show);
   close_tag.style.display = "block";
   bar_show = setTimeout(function() {close_tag.style.display = "none"}, 1000);
  }
}