跟我做背景变暗，弹出提示层的功能,而且增加了对Select对象的支持

< html >    
   < head >    
   </ head >    
   < body >    
   < p    align ="center" >    
   < script > ...    
  function   locking()...{   
  document.all.ly.style.display="block";   
  document.all.ly.style.width=document.body.clientWidth;   
  document.all.ly.style.height=document.body.clientHeight;   
  document.all.Layer2.style.display='block';   
  }   
  function   Lock_CheckForm(theForm)...{   
  if(theForm.P_USERPASS.value=='')...{alert("错误：请输入你的用户密码!");theForm.P_USERPASS.focus();return   false;}   
  if(theForm.P_USERPASS.value   !='123')...{alert("错误：密码错误!");theForm.P_USERPASS.value='';theForm.P_USERPASS.focus();return   false;}   
  else...{document.all.ly.style.display='none';document.all.Layer2.style.display='none';}   
  return   false;   
  }   
   </ script >    
   < img    src =http://www.shangdu.com/images/517s1.gif >    
    
   </ p >    
   < p    align ="center" >    
    
   < INPUT    TYPE ="button"    value ="系统锁定"    onclick ="locking()" >    
   </ p >    
   < div    id ="ly"    style ="position:absolute;top:0px;FILTER:   alpha(opacity=60);background-color:#777;   z-index:2;   left:   0px;display:none;" >     </ div >    
    
   <!--          浮层框架开始          -->    
               < div    id ="Layer2"    align ="center"    style ="position:absolute;   z-index:3;   width:   540;   height:170px;left:expression((document.body.offsetWidth-540)/2);   top:   expression((document.body.offsetHeight-170)/2);background-color:#fff;display:none;"    valign ="center" >      
   < form    method ="POST"    action =""    onsubmit ="return   Lock_CheckForm(this);" >    
       < TABLE    width =540    height =170    border =0    cellpadding =0    cellspacing =0    style ="border:0   solid   #e7e3e7;border-collapse:   collapse" >    
       < TR >    
       < TD    style ="background-color:#73A2d6;color:#fff;padding-left:4px;padding-top:2px;font-weight:bold;font-size:14px;"    height =27    valign ="center" > [ &nbsp; 警 &nbsp; 告 &nbsp; ] </ TD >    
       </ TR >    
       < TR >    
       < TD    align ="center"    valign ="center" > 请输入解除锁定密码 < p >< input    type ="text"    name ="P_USERPASS"    size ="20" ></ TD >    
       </ TR >    
       < TR >    
       < TD    height =30    align ="center" >< INPUT    type ="submit"    value ="     确         定     " ></ TD >    
       </ TR >    
       </ TABLE >    
   </ form >    
               </ div >      
   <!--          浮层框架结束          -->    
   </ body >    
   </ html >    
  

  < script    language ="JavaScript" > ...    
  <!--   
  var   oPopup=window.createPopup();   
  var   oPopBody=oPopup.document.body;   
  var   colorArr=["#F7F7F7","#E7E7E7","#D7D7D7","#D4D4D4","#BCBCBC","#ACACAC"];   
  var   i=0;   
  var   iMaxLength=6;   
  var   timer=null;   
  function   showPopup()...{   
  var   oBody=document.body;   
  oPopBody.attachEvent("oncontextmenu",cancelEvent);   
  oPopBody.bgColor="#FFFFFF";   
  var   strHTML=""   
  strHTML+='<center><div   align="center"   style="border:solid   2px   #00FFFF;valign:middle;   width:400;   height:200">请您选中要操作的信件!<input   type="button"   value="确定"   onclick="parent.hidePopup()"></div></center>';   
  oPopBody.innerHTML=strHTML;   
  oPopup.show(0,0,oBody.clientWidth,oBody.clientHeight,document.body);   
  chgBgcolor();   
  }   
  function   chgBgcolor()...{   
  if(i<iMaxLength)...{   
  oPopBody.bgColor=colorArr[i++];   
  timer=setTimeout(chgBgcolor,100);   
  }   
  else...{   
  clearTimeout(timer);   
  i=0;   
  }   
  }   
  function   cancelEvent()...{   
  return   false;   
  }   
  function   hidePopup()...{   
  oPopup.hide();   
  }   
  //-->   
   </ script >    
   < input    type ="button"    onclick ="showPopup()"    value ="操作有误" >

  < script    language ="JavaScript" > ...    
  <!--   
  var   oPopup=window.createPopup();   
  var   oPopBody=oPopup.document.body;   
  var   colorArr=["#F7F7F7","#E7E7E7","#D7D7D7","#D4D4D4","#BCBCBC","#ACACAC"];   
  var   i=0;   
  var   iMaxLength=6;   
  var   timer=null;   
  function   showPopup()...{   
  var   oBody=document.body;   
  oPopBody.attachEvent("oncontextmenu",cancelEvent);   
  oPopBody.bgColor="#FFFFFF";   
  var   strHTML=""   
  strHTML+='<center><div   align="center"   style="border:solid   2px   #00FFFF;valign:middle;   width:400;   height:200">请您选中要操作的信件!<input   type="button"   value="确定"   onclick="parent.hidePopup()"></div></center>';   
  oPopBody.innerHTML=strHTML;   
  oPopup.show(0,0,oBody.clientWidth,oBody.clientHeight,document.body);   
  chgBgcolor();   
  }   
  function   chgBgcolor()...{   
  if(i<iMaxLength)...{   
  oPopBody.bgColor=colorArr[i++];   
  timer=setTimeout(chgBgcolor,100);   
  }   
  else...{   
  clearTimeout(timer);   
  i=0;   
  }   
  }   
  function   cancelEvent()...{   
  return   false;   
  }   
  function   hidePopup()...{   
  oPopup.hide();   
  }   
  //-->   
   </ script >    
   < input    type ="button"    onclick ="showPopup()"    value ="操作有误" >