为什么这个页面总找不到Span标签

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml" >
<head><title>
无标题页
</title></head>
<body>
 <form name="form1" method="post" action="Default.aspx" id="form1">
<div>
<input type="hidden" name="__VIEWSTATE" id="__VIEWSTATE" value="/wEPDwUKLTQxNzA1NjY0MWRkE6LzRxBpVk7xWCOrIjiDJYObxEQ=" />
</div> <div>
  </div>

 <script type="text/javascript">
 var xmlHttp;
 var key;
 var bar_color="blue";

 var filename;
 var filesize;
 var begintime;
function createXmlHttpRequest(){
if(window.ActiveXObject){
xmlHttp=new ActiveXObject("Msxml2.XMLHTTP");
}
else if(window.XMLHttpRequest){
xmlHttp=new XMLHttpRequest();
}
}

function go(){
 OpenUpload();
 createXmlHttpRequest();
 checkDiv();
 begintime=new Date();
 var url="../UploadControl/UploadControl/UploadAjax.aspx?task=create"+"&begintime="+begintime.getTime();
 xmlHttp.open("GET",url,true);
 xmlHttp.onreadystatechange=goCallback;
 xmlHttp.send(null);
}

function checkDiv(){
 clearBar();
}

function clearBar(){
 for(var i=1;i<=100;i++){
 var elem=document.getElementById("Span"+i);
 elem.style.backgroundColor="blue";
 }
}

function goCallback(){
 if(xmlHttp.readyState==4)
{
if(xmlHttp.status==200)
{
 setTimeout("pollServer()",1000);
 var xml=xmlHttp.responseXML;

 var speed=xml.getElementsByTagName("speed")[0].firstChild.data;
 var spanSpeed=document.getElementById("speed");
 spanSpeed.innerHTML="上传速度:"+speed+"KB/S";

 var percent=xml.getElementsByTagName("percent")[0].firstChild.data;
 var spanPercent=document.getElementById("percent");
 spanPercent.innerHTML=percent+"%";
}
}
}

function pollServer(){
 if(xmlHttp==null)
 return;
 var url="../UploadControl/UploadControl/UploadAjax.aspx?task=poll"+"&begintime="+begintime.getTime()+"&now="+new Date().getTime();
 xmlHttp.open("GET",url,true);
 xmlHttp.onreadystatechange=pollCallback;
 xmlHttp.send(null);
}

function pollCallback(){
 if(xmlHttp.readyState==4)
{
if(xmlHttp.status==200)
{
 var xml=xmlHttp.responseXML;

 var speed=xml.getElementsByTagName("speed")[0].firstChild.data;
 var spanSpeed=document.getElementById("speed");
 spanSpeed.innerHTML="上传速度:"+speed+"KB/S";

 var percent=xml.getElementsByTagName("percent")[0].firstChild.data;
 var spanPercent=document.getElementById("percent");
 spanPercent.innerHTML=percent+"%";
 var percent=parseInt(percent);
 for(var i=1;i<=percent;i++){
 var elem=document.getElementById("Span"+i);
 elem.style.backgroundColor=bar_color;
 }
 if(percent<100){
 setTimeout("pollServer()",1000);
 }
 else
 {
 //CloseUpload();
 }
}
}
}

function CloseUpload(){
 var mask=document.getElementById("mask");
 var progressFrame=document.getElementById("progressBarFrame");
 mask.style.visibility="hidden";
 progressFrame.style.visibility="hidden";
 xmlHttp.abort();
 document.fileuploadframe.location="../UploadControl/UploadControl/UpLoadWindow.aspx";
 xmlHttp=null;
}

function OpenUpload(){
 var allWidth=document.body.clientWidth;
 var mask=document.getElementById("mask");
 var progressFrame=document.getElementById("progressBarFrame");
 mask.style.width=document.body.clientWidth.toString();
 mask.style.height=document.body.clientHeight.toString();
 mask.style.visibility="visible";
 var left=(allWidth-650)/2;
 progressFrame.style.left=left.toString();
 var top=(document.body.scrollTop+window.screen.availHeight-120)/2;
 progressFrame.style.top=top.toString();
 progressFrame.style.visibility="visible";
 }
</script>
<iframe name="fileuploadframe" frameborder="0" scrolling="no" src="../UploadControl/UploadControl/UpLoadWindow.aspx" width="560px" height="80px">

</iframe>

解决方案 »

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<div id="mask" style=" visibility:hidden ;color:Red; position:absolute;top:0px; left:0px; z-index:4; border:solid blue 1px;background-color:Blue;filter:ALPHA(opacity=40); width:100%; height:100%">
 <input type="button" id="hiddenbutton" style=" visibility:hidden" onclick="go();" />
</div>
<div id="progressBarFrame" style=" visibility:hidden ;position:absolute; text-align:center; vertical-align:middle; z-index:5; border:solid blue 1px;background-color:White;width:650px; height:120px;">
 <div style=" background-color:MenuText">uncomplete</div>
 <div style=" text-align:center; font-size:smaller">上传速度:KB/S</div> <div id="progressBar" style=" border:solid black 1px; width:605px; height:30px; padding:0px; margin:0px">
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 </div>
 

 <div>
 <input id="btnStop" type="button" value="停止上传" onclick="CloseUpload();" />
 </div>
</div>
 </form></body></html>var elem=document.getElementById("Span11");elem.style.backgroundColor="blue";错误： elem is null
源文件：javascript:%20var%20elem=document.getElementById("Span11");elem.style.backgroundColor="blue";
行：1
<div id="mask" style=" visibility:hidden ;color:Red; position:absolute;top:0px; left:0px; z-index:4; border:solid blue 1px;background-color:Blue;filter:ALPHA(opacity=40); width:100%; height:100%">
 <input type="button" id="hiddenbutton" style=" visibility:hidden" onclick="go();" />
</div>
<div id="progressBarFrame" style=" visibility:hidden ;position:absolute; text-align:center; vertical-align:middle; z-index:5; border:solid blue 1px;background-color:White;width:650px; height:120px;">
 <div style=" background-color:MenuText">uncomplete</div>
 <div style=" text-align:center; font-size:smaller">上传速度:KB/S</div> <div id="progressBar" style=" border:solid black 1px; width:605px; height:30px; padding:0px; margin:0px">
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 </div>
 

 <div>
 <input id="btnStop" type="button" value="停止上传" onclick="CloseUpload();" />
 </div>
</div>
 </form></body></html>var elem=document.getElementById("Span11");elem.style.backgroundColor="blue";错误： elem is null
源文件：javascript:%20var%20elem=document.getElementById("Span11");elem.style.backgroundColor="blue";
行：1
<div id="mask" style=" visibility:hidden ;color:Red; position:absolute;top:0px; left:0px; z-index:4; border:solid blue 1px;background-color:Blue;filter:ALPHA(opacity=40); width:100%; height:100%">
 <input type="button" id="hiddenbutton" style=" visibility:hidden" onclick="go();" />
</div>
<div id="progressBarFrame" style=" visibility:hidden ;position:absolute; text-align:center; vertical-align:middle; z-index:5; border:solid blue 1px;background-color:White;width:650px; height:120px;">
 <div style=" background-color:MenuText">uncomplete</div>
 <div style=" text-align:center; font-size:smaller">上传速度:KB/S</div> <div id="progressBar" style=" border:solid black 1px; width:605px; height:30px; padding:0px; margin:0px">
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 </div>
 

 <div>
 <input id="btnStop" type="button" value="停止上传" onclick="CloseUpload();" /> </div>
</div>
 </form></body></html>
错误： elem is null
源文件：javascript:%20var%20elem=document.getElementById("Span11");elem.style.backgroundColor="blue";
行：1
看情况应该是在调用时,将空格URL编码了(%20),
先修改脚本,避免空格function clearBar(){
 for(var i=1;i<=100;i++){
 var elem=document.getElementById("Span"+i);
 elem.style.backgroundColor="blue";
 }
 }改为function clearBar(){
 for(var i=1;i<=100;i++){document.getElementById("Span"+i).style.backgroundColor="blue";}
}看还有没有出错,若仍出错,
请查看一下文档中哪里调用了函数clearBar();
再议
javascript:document.getElementById("Span11").style.backgroundColor='blue';