Jquery Js ExtJs 弹出带图层的自定义图片显示

<style>

html,body {

 font-size: 12px;

 margin: 0px;

 height: 100%;

}

.mesWindow {

 border: #666 1px solid;

 background: #fff;

}

.mesWindowTop {

 border-bottom: #eee 1px solid;

 margin-left: 4px;

 padding: 3px;

 font-weight: bold;

 text-align: left;

 font-size: 12px;

}

.mesWindowContent {

 margin: 4px;

 font-size: 12px;

}

.mesWindow .close {

 height: 15px;

 width: 28px;

 border: none;

 cursor: pointer;

 text-decoration: underline;

 background: #fff

}

</style>

<script>

 var isIe = (document.all) ? true : false;

 //设置select的可见状态

 function setSelectState(state) {

  var objl = document.getElementsByTagName('select');

  for ( var i = 0; i < objl.length; i++) {

   objl[i].style.visibility = state;

  }

 }

 function mousePosition(ev) {

  if (ev.pageX || ev.pageY) {

   return {

    x : ev.pageX,

    y : ev.pageY

   };

  }

  return {

   x : ev.clientX + document.body.scrollLeft

     - document.body.clientLeft,

   y : ev.clientY + document.body.scrollTop - document.body.clientTop

  };

 }

 //弹出方法

 function showMessageBox(wTitle, content, pos, wWidth) {

  closeWindow();

  var bWidth = parseInt(document.documentElement.scrollWidth);

  var bHeight = parseInt(document.documentElement.scrollHeight);

  if (isIe) {

   setSelectState('hidden');

  }

  var back = document.createElement("div");

  back.id = "back";

  var styleStr = "top:0px;left:0px;position:absolute;background:#666;width:"

    + bWidth + "px;height:" + bHeight + "px;";

  styleStr += (isIe) ? "filter:alpha(opacity=0);" : "opacity:0;";

  back.style.cssText = styleStr;

  document.body.appendChild(back);

  showBackground(back, 50);

  var mesW = document.createElement("div");

  mesW.id = "mesWindow";

  mesW.className = "mesWindow";

  mesW.innerHTML = "<div class='mesWindowTop' ><table  width='100%' height='100%'><tr><td>"

    + wTitle

    + "</td><td style='width:1px;'><input type='button' title='关闭窗口' class='close' value='关闭' /></td></tr></table></div><div  class='mesWindowContent' id='mesWindowContent'>"

    + content + "</div><div class='mesWindowBottom'></div>";

  styleStr = "left:0px;top:25px;position:absolute;";

  mesW.style.cssText = styleStr;

  document.body.appendChild(mesW);

 }

 //让背景渐渐变暗

 function showBackground(obj, endInt) {

  if (isIe) {

   obj.filters.alpha.opacity += 1;

   if (obj.filters.alpha.opacity < endInt) {

    setTimeout(function() {