拒绝session丢失 利用DIV层实现对模态窗口的模拟

 使用window.showModalDialog进行信息的提示，相当方便，也容易控制外观和布局。但是存在一个严重的问题，就是Session丢失。当在A页面进行showModalDialog时，弹出的模态窗口open新页面或new dialog()时，会得不到A页面中的Session，这样就严重地限制了他的使用范围。

进一步的使用模式窗口可以发现session的丢失总是便随页面的刷新
1.在普通页面中弹出模式窗口且进行new dialog()操作时 会造成该进程中所有页面session的丢失

2.在模式窗口嵌套使用时 弹出的模式窗口并不会使父模式窗口的session丢失 但是会取不到父模式窗口的值

3.在弹出的模式窗口中使用js脚本需要验证表单时 如果出现return true or false之类的语句，会造成模态窗口session的丢失。

用showModalDialog经常出现这样那样奇怪的问题，因此最好少用showModalDialog。替代的方法就是用DIV来模拟实现模式窗口相同的功能。

html代码如下

< div  id ="id2" >   <!-- 这个是弹出的层 -->
   < table  height ="100"  width ="200" >
     < tr >
       < td >                                 
       < div  id ="ShowMSG" ></ div >
       </ td >
     </ tr >
     < tr >
< td  align ="center" >< input  class ="Button60"  onclick ="divhide()"  type ="button"  value ="关闭"  name ="btnDo">

</ td >
     </ tr >
   </ table >
</ div >
< div  id ="id1" > 这里是弹出层后的背景 可以不放内容 </ div >

在Css中设置弹出窗口的颜色背景透明度等

#id1 ... {width:100%;height:100%;background-color:#000;position:absolute;top:0;left:0;z-index:49;display:none;  filter:progid:DXImageTransform.Microsoft.Alpha(opacity=25);
}
#id2 ... {top:200px;position:absolute;z-index:50;display:none;border:3px solid #E5E5E5; left:100px;background-color:white;}

js代码如下 可以对层进行拖拽 随意进行移动

function  divshow(showmsg) ... { //弹出窗口
document.getElementById("id1").style.height=window.screen.height+"px";
document.getElementById("id1").style.width=window.screen.width+"px";
document.getElementById("id1").style.display='block';
document.getElementById("id2").style.display='block';
document.getElementById("ShowMSG").innerText = showmsg;
}
function  divhide() ... {  //隐藏窗口 
document.getElementById("id1").style.display='none'
document.getElementById("id2").style.display='none'
}

self.onError = null ;                              
currentX  =  currentY  =   0 ;                               
whichIt  =   null ;                                         
lastScrollX  =   0 ; lastScrollY  =   0 ;                              
NS  =  (document.layers)  ?   1  :  0 ;                             
IE  =  (document.all)  ?   1 :  0 ;                              
<!--  STALKER CODE  -->                               
function  heartBeat()  ... {                              
if(IE) ...{ diffY = document.body.scrollTop; diffX = document.body.scrollLeft; }                             
if(NS) ...{ diffY = self.pageYOffset; diffX = self.pageXOffset; }           
if(diffY != lastScrollY) ...{            
percent = .1 * (diffY - lastScrollY);    
if(percent > 0) percent = Math.ceil(percent); 
else percent = Math.floor(percent);  
if(IE) document.all.id2.style.pixelTop += percent;  
if(NS) document.id2.top += percent;                 
lastScrollY = lastScrollY + percent;      
}                       
if(diffX != lastScrollX) ...{       
percent = .1 * (diffX - lastScrollX);     
if(percent > 0) percent = Math.ceil(percent);       
else percent = Math.floor(percent);                   
if(IE) document.all.id2.style.pixelLeft += percent;        
if(NS) document.id2.left += percent;       
lastScrollX = lastScrollX + percent;                     
}                           
}                          
<!--   / STALKER CODE  -->               
<!--  DRAG DROP CODE  -->               
function  checkFocus(x,y)  ... {         
stalkerx = document.id2.pageX;     
stalkery = document.id2.pageY;                        
stalkerwidth = document.id2.clip.width;              
stalkerheight = document.id2.clip.height;                         
if( (x > stalkerx && x < (stalkerx+stalkerwidth)) && (y > stalkery && y < (stalkery+stalkerheight))) return true;                      
else return false;        
}                      
function  grabIt(e)  ... {            
if(IE) ...{                            
whichIt = event.srcElement; 
while (whichIt.id.indexOf("id2") == -1) ...{    
whichIt = whichIt.parentElement;                           
if (whichIt == null) ...{ return true; }         
 }                            
whichIt.style.pixelLeft = whichIt.offsetLeft;                              
whichIt.style.pixelTop = whichIt.offsetTop;                          
currentX = (event.clientX + document.body.scrollLeft);                       
currentY = (event.clientY + document.body.scrollTop);                        
} else ...{                             
window.captureEvents(Event.MOUSEMOVE);    
if(checkFocus (e.pageX,e.pageY)) ...{                            
whichIt = document.id2;                              
stalkerTouchedX = e.pageX-document.id2.pageX;      
StalkerTouchedY = e.pageY-document.id2.pageY;          
}                              
}                            
return true;                        
}                             
function  moveIt(e)  ... {               
if (whichIt == null) ...{ return false; }       
if(IE) ...{                             
newX = (event.clientX + document.body.scrollLeft);                           
newY = (event.clientY + document.body.scrollTop);                
distanceX = (newX - currentX);    distanceY = (newY - currentY);   
currentX = newX;    currentY = newY;                       
whichIt.style.pixelLeft += distanceX;                          
whichIt.style.pixelTop += distanceY;                      
if(whichIt.style.pixelTop < document.body.scrollTop) whichIt.style.pixelTop = document.body.scrollTop;   
 if(whichIt.style.pixelLeft < document.body.scrollLeft) whichIt.style.pixelLeft = document.body.scrollLeft; if(whichIt.style.pixelLeft > document.body.offsetWidth - document.body.scrollLeft - whichIt.style.pixelWidth - 20) whichIt.style.pixelLeft = document.body.offsetWidth - whichIt.style.pixelWidth - 20;
if(whichIt.style.pixelTop > document.body.offsetHeight + document.body.scrollTop - whichIt.style.pixelHeight - 5) whichIt.style.pixelTop = document.body.offsetHeight + document.body.scrollTop - whichIt.style.pixelHeight - 5;  
event.returnValue = false;  
} else ...{   
whichIt.moveTo(e.pageX-StalkerTouchedX,e.pageY-StalkerTouchedY); 
if(whichIt.left < 0+self.pageXOffset) whichIt.left = 0+self.pageXOffset; 
if(whichIt.top < 0+self.pageYOffset) whichIt.top = 0+self.pageYOffset;  
if( (whichIt.left + whichIt.clip.width) >= (window.innerWidth+self.pageXOffset-17)) whichIt.left = ((window.innerWidth+self.pageXOffset)-whichIt.clip.width)-17; 
if( (whichIt.top + whichIt.clip.height) >= (window.innerHeight+self.pageYOffset-17)) whichIt.top = ((window.innerHeight+self.pageYOffset)-whichIt.clip.height)-17; 
return false;} 
return false;  
}    
function  dropIt()  ... {     
whichIt = null;     
if(NS) window.releaseEvents (Event.MOUSEMOVE);  
return true;             
 }                      
<!--  DRAG DROP CODE  -->   
if (NS)  ... {    
window.captureEvents(Event.MOUSEUP|Event.MOUSEDOWN);
window.onmousedown = grabIt;
window.onmousemove = moveIt; 
window.onmouseup = dropIt; 
}               
if (IE)  ... {                     
document.onmousedown = grabIt;    
document.onmousemove = moveIt;   
document.onmouseup = dropIt;          
 }                          
if (NS  ||  IE) action  =  window.setInterval( " heartBeat() " , 1 )

在页面中调用divshow()就可以弹出仿照的模式窗口，这样就不会出现丢失session的问题，而且视觉效果很好。Created by jecray