使用HTML5和Ajax上传进度条

Question

我目前正在处理一个包含HTML5和Ajax的上传进度条。

我使用javascript从我的html表单发送数据。

这是我的javascript：

function _(el){
    return document.getElementById(el);
}
// Submit the upload form
function uploadFiles(){
    var file = _("upfile_0").files[0];
    //alert(file.name+" | "+file.size+" | "+file.type);
    var formdata = new FormData();
    formdata.append("upfile_0", file);
    var ajax = new XMLHttpRequest();
    ajax.upload.addEventListener("progress", progressHandler, false);
    ajax.addEventListener("load", completeHandler, false);
    ajax.addEventListener("error", errorHandler, false);
    ajax.addEventListener("abort", abortHandler, false);
    ajax.open("POST", "file_upload_parser.php");
    ajax.send(formdata);

    if(checkFileNameFormat()){ return false; }
    if(checkDisallowFileExtensions()){ return false; }
    if(checkAllowFileExtensions()){ return false; }
    if(checkNullFileCount()){ return false; }
    if(checkDuplicateFileCount()){ return false; }

    var total_uploads = 0;

    for(var i = 0; i < upload_range; i++){
        if(document.form_upload.elements['upfile_' + i].value != ""){ total_uploads++; }
    }

    document.getElementById('total_uploads').innerHTML = total_uploads;
    document.form_upload.submit();
    document.getElementById('upload_button').disabled = true;

    iniProgressRequest();
    getElapsedTime();

    for(var i = 0; i < upload_range; i++){ document.form_upload.elements['upfile_' + i].disabled = true; }  

}
function progressHandler(event){
    _("loaded_n_total").innerHTML = "Uploaded "+event.loaded+" bytes of "+event.total;
    var percent = (event.loaded / event.total) * 100;
    _("progressBar").value = Math.round(percent);
    _("status").innerHTML = Math.round(percent)+"% uploaded... please wait";
}
function completeHandler(event){
    _("status").innerHTML = event.target.responseText;
    _("progressBar").value = 0;
}
function errorHandler(event){
    _("status").innerHTML = "Upload Failed";
}
function abortHandler(event){
    _("status").innerHTML = "Upload Aborted";
}

这是我的HTML来选择文件并打印进度条：

        <form name="form_upload" method="post" enctype="multipart/form-data"  action="[var.path_to_upload_script]" style="margin: 0px; padding: 0px;">
          <noscript><input type="hidden" name="no_script" value="1" /></noscript>
          <input type="hidden" name="title" value="[var.title]" />
    <input type="hidden" name="description" value="[var.description]" />
    <input type="hidden" name="tags" value="[var.tags]" />
    <input type="hidden" name="location_recorded" value="[var.location_recorded]" />
    <input type="hidden" name="allow_comments" value="[var.allow_comments]" />
    <input type="hidden" name="allow_embedding" value="[var.allow_embedding]" />
    <input type="hidden" name="public_private" value="[var.public_private]" />
    <input type="hidden" name="channel" value="[var.channel]" />
    <input type="hidden" name="channel_name" value="[var.channel_name]" />
    <input type="hidden" name="sub_cat" value="[var.sub_cat]" />
    <input type="hidden" name="form_submitted" value="yes" />

    <div id="upload_slots"><span class="font5_16"><b>[var.lang_please_upload]</b></span><input type="file" name="upfile_0" id="upfile_0" /></div>
      <progress id="progressBar" value="0" max="100" style="width:300px;"></progress>
      <p id="status"></p>
      <p id="loaded_n_total"></p>
    <noscript><br><input type="reset" name="no_script_reset" value="Reset" />&nbsp;&nbsp;&nbsp;<input type="submit" name="no_script_submit" value="Upload" /></noscript>
    </form>
    <br>
    <script language="javascript" type="text/javascript">
        document.writeln('<input type="button" name="reset_button" value="Reset" onClick="resetForm();">&nbsp;&nbsp;&nbsp;<input type="button" id="upload_button" name="upload_button" value="Upload" onClick="uploadFiles();">');
    </script>

当我从我的Javascript中删除这一行时：

document.getElementById('total_uploads').innerHTML = total_uploads;
document.form_upload.submit();
document.getElementById('upload_button').disabled = true;

上传进度条正在工作，并显示所有内容，但它并不是真正的子表单。

那么我怎样才能使这个脚本既可以用于子表单并显示上传进度条呢？