网页下载文件期间如何防止用户对网页进行其他操作

function lockScreen() 
{ 
sWidth=$(window).width(); 
sHeight=$(window).height(); 
var bgObj=document.createElement("div"); 
bgObj.setAttribute('id','bgDiv'); 
bgObj.style.position="absolute"; 
bgObj.style.top="0"; 
bgObj.style.background="#CCCCCC"; 
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"; 
if(sWidth < 860) 
{ 
bgObj.style.width="860px"; 
} 
bgObj.style.zIndex = "10000"; 
document.body.appendChild(bgObj); 
}

<pre name="code" class="cpp">char *configDownloadToken = "finishedDownloadFile"; 
printf("Content-Type: application/octet-stream\nContent-Length: %ld\n", s.st_size); 
printf( "Set-Cookie:configDownloadToken=%s; path=/; \r\n ",configDownloadToken); 
printf("Content-Disposition: attachment; filename=\"%s\"\n", strrchr(filename,'/') + 1); 
printf("Connection: close\n\n");

var configDownloadCheckTimer; 
$(document).ready(function () { 
configDownloadCheckTimer = window.setInterval(function() { 
var cookieValue = $.cookie('configDownloadToken'); 
if (cookieValue === "finishedDownloadFile") 
{ 
refreshPage(); 
finishDownload(); 
} 
}, 1000); 
}); 

function finishDownload() { 
window.clearInterval(configDownloadCheckTimer); 
$.removeCookie('configDownloadToken'); //clears this cookie value 
}