html5 异步文件上传（超简洁）--基于XMLHttpRequest 2 实现-null-ICode联盟

内部原理这里就不详述了，后面给出原生代码：

1、jquery实现

html 代码：

<form id="myForm">
    <input type="file" id="u_photo" name="u_photo" />
    <input type="button" id="submit-btn" value="上传" />
</form>

jquery代码：

$("#submit-btn").on(\'click\', function() {
    $.ajax({
        url:"/test/upload",
        type:"post",
        data:new FormData($("#myForm").get(0)),
        //十分重要，不能省略
        cache: false,
        processData: false,
        contentType: false,
        success: function () {
            alert("上传成功！");
        }
    });
});

2、原生实现代码

<!DOCTYPE html>
<html>
<head>
    <title>使用XMLHttpRequest上传文件</title>
    <script type="text/javascript">
    var xhr = new XMLHttpRequest();

    //监听选择文件信息
    function fileSelected() {
        //HTML5文件API操作
          var file = document.getElementById(\'fileName\').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 = \'Name: \' + file.name;
            document.getElementById(\'fileSize\').innerHTML = \'Size: \' + fileSize;
            document.getElementById(\'fileType\').innerHTML = \'Type: \' + file.type;
          }
        }

    //上传文件
    function uploadFile() {
          var fd = new FormData();
          //关联表单数据,可以是自定义参数
          fd.append("name", document.getElementById(\'name\').value);
          fd.append("fileName", document.getElementById(\'fileName\').files[0]);

          //监听事件
          xhr.upload.addEventListener("progress", uploadProgress, false);
          xhr.addEventListener("load", uploadComplete, false);
          xhr.addEventListener("error", uploadFailed, false);
          xhr.addEventListener("abort", uploadCanceled, false);
          //发送文件和表单自定义参数
          xhr.open("POST", "upload.php");
          xhr.send(fd);
        }
    //取消上传
    function cancleUploadFile(){
        xhr.abort();
    }

    //上传进度
    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\';
          }
    }

    //上传成功响应
    function uploadComplete(evt) {
        //服务断接收完文件返回的结果
        alert(evt.target.responseText);
    }

    //上传失败
    function uploadFailed(evt) {
         alert("上传失败");
    }
    //取消上传
    function uploadCanceled(evt) {
        alert("您取消了本次上传.");
    }
    </script>
</head>
<body>

<div class="row">
      <label for="fileToUpload">选择文件</label>
<input type="file" name="fileName" id="fileName" onchange="fileSelected();"/>
    </div>
<div id="fileName"></div>
<div id="fileSize"></div>
<div id="fileType"></div>
<div class="row">
上传者：<input type="text" name="name" id="name"/>
<input type="button" onclick="uploadFile()" value="上传" />
<input type="button" onclick="cancleUploadFile()" value="取消" />
    </div>
<div id="progressNumber"></div>


</body>
</html>