HTML5 上传文件显示进度的方法

HTML部分：

<form id="form1"  enctype="multipart/form-data">
<div class="toptool">
       <input type="file" name="fileToUpload" id="fileToUpload" onchange="fileSelected();"/>
       <input type="button" onclick="uploadFile()" style="display:none;" value="上传" />
        <div id="fileName"></div>
    <div id="fileSize"></div>
    <div id="fileType"></div>
       <div id="progressNumber"></div>
    </div>
</form>

JS部分：

function fileSelected() {
            var file = document.getElementById('fileToUpload').files[0];
            if (file) {
                var fileSize = 0;
                if (file.size > 1024 * 1024)
                    fileSize = (Math.round(file.size * 100 / (1024 * 1024)) / 100).toString() + 'MB';
                else
                    fileSize = (Math.round(file.size * 100 / 1024) / 100).toString() + 'KB';
                document.getElementById('fileName').innerHTML = '名称: ' + file.name;
                document.getElementById('fileSize').innerHTML = '大小: ' + fileSize;
                document.getElementById('fileType').innerHTML = '类型: ' + file.type;
                uploadFile();
            }
        }
        function uploadFile() {
            var fd = new FormData();
            fd.append("fileToUpload", document.getElementById('fileToUpload').files[0]);
            var xhr = new XMLHttpRequest();
            xhr.upload.addEventListener("progress", uploadProgress, false);
            xhr.addEventListener("load", uploadComplete, false);
            xhr.addEventListener("error", uploadFailed, false);
            xhr.addEventListener("abort", uploadCanceled, false);
            xhr.open("POST", document.location);//修改成自己的接口
            xhr.send(fd);
        }
        function uploadProgress(evt) {
            if (evt.lengthComputable) {
                var percentComplete = Math.round(evt.loaded * 100 / evt.total);
                document.getElementById('progressNumber').innerHTML = percentComplete.toString() + '%';
            }
            else {
                document.getElementById('progressNumber').innerHTML = 'unable to compute';
            }
        }
        function uploadComplete(evt) {
            /* 服务器端返回响应时候触发event事件*/
            alert(evt.target.responseText);
        }
        function uploadFailed(evt) {
            alert("There was an error attempting to upload the file.");
        }
        function uploadCanceled(evt) {
            alert("The upload has been canceled by the user or the browser dropped the connection.");
        }