function DIVWindow(str){
        var msgw,msgh,bordercolor;
        msgw=400;//提示窗口的宽度
        msgh=100;//提示窗口的高度
        titleheight=25 //提示窗口标题高度
        bordercolor="#336699";//提示窗口的边框颜色
        titlecolor="#99CCFF";//提示窗口的标题颜色
        
        var sWidth,sHeight;
        sWidth=document.body.offsetWidth;
        sHeight=screen.height;
        var bgObj=document.createElement("div");
        bgObj.setAttribute('id','bgDiv');
        bgObj.style.position="absolute";
        bgObj.style.top=document.body.scrollTop;
        bgObj.style.background="#777";
        bgObj.style.filter="progid:DXImageTransform.Microsoft.Alpha(style=3,opacity=25,finishOpacity=75";
        bgObj.style.opacity="0.6";
        bgObj.style.left="0";
        
        bgObj.style.width=sWidth + "px";
        bgObj.style.height=sHeight + "px";
        bgObj.style.zIndex = "9999";
        bgObj.style.textAlign = "right";
        bgObj.style.padding = "5px";
        
        
       	var closediv=document.createElement("div");
       	closediv.innerHTML="<input style='border:1px solid #ccc;background:#fff;' type=button value='关闭' >";
       	closediv.style.width="100%";
       	closediv.style.fontSize="12px";
       	closediv.style.cursor ="pointer";
       	closediv.styleFloat ="right";
       	closediv.style.textAlign = "right";
        closediv.onclick=function (){
          document.body.removeChild(bgObj);
          document.body.removeChild(htmlBody);
          document.body.style.overflow="auto";
        }
        
        var img=document.createElement("img");
        	img.src=str;
        	a=img.width/800;
			b=(img.height/580);
			if(a>1 && b>1){
				if(a>b){
						img.width=img.width/a;
						img.height=img.height/a;
						
				}else{
					img.width = img.width/b;
					img.height=img.height/b;
				}
				
			}
			bgstyle="width:"+img.width+"px;height:"+(img.height+20)+"px;";
		
        $html ="<div id=imgdivbg style='"+bgstyle+"border:1px solid #999;text-alingn:right;background:#fff;padding:3px;'>"		
        			+"<div id=imgdiv style='text-align:right;border:1px solid #999;background:url("+str+");background-repeat:no-repeat;background-position:center middle;'>"
        			+"</div>"		
        	 +"</div>";
        	
        var htmlBody =document.createElement("div");
        	htmlBody.style.width="100%";
        	htmlBody.style.textAlign="center";
        	htmlBody.style.position="absolute";
        	htmlBody.style.overflow='auto';
        	htmlBody.style.zIndex = "10000";
        	htmlBody.style.top	=(document.body.scrollTop+5)+"px";
        	htmlBody.style.left	= "0px";
      
        htmlBody.innerHTML=$html;
        document.body.style.overflow="hidden";
        //document.body.scrollTop =0;
        document.body.appendChild(bgObj);
        document.body.appendChild(htmlBody);
   	    var imgdivbg=document.getElementById("imgdivbg");   
        imgdivbg.appendChild(closediv); 
        var imgdiv=document.getElementById("imgdiv");
        imgdiv.appendChild(img);
        
        document.onkeydown=function(){ 
			if(window.event.keyCode==27){ 
			closediv.onclick();
			}
		}

}

function DT_image(img_id,limit_width,limit_height){
       var   width,height; 
       if(img_id){ 
        width=img_id.width; 
        height=img_id.height; 
        if(width/height>limit_width/limit_height){
          if(width>limit_width)  
            img_id.width=limit_width;
       }else{
         if(height>limit_height)  
            img_id.height=limit_height;
      }  
   } 
}