PC端上传文件多半用插件，引入flash都没关系，但是移动端要是还用各种冗余的插件估计得被喷死，项目里面需要做图片上传的功能，既然H5已经有相关的接口且兼容性良好，当然优先考虑用H5来实现。

JS代码：

<script type="text/javascript">
        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 = 'Name: ' + file.name;
                document.getElementById('fileSize').innerHTML = 'Size: ' + fileSize;
                document.getElementById('fileType').innerHTML = 'Type: ' + file.type;
            }
        }
 
        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", "/Home/Upload");
            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) {
            /* This event is raised when the server send back a response */
            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.");
        }
    </script>

Html代码：

<h1>单文件上传</h1>
  <form id="form1" enctype="multipart/form-data" method="post" action="/Home/Upload">
    <div class="row">
      <label for="fileToUpload">Select a File to Upload</label><br />
      <input type="file" name="fileToUpload" id="fileToUpload" onchange="fileSelected();"/>
    </div>
    <div id="fileName"></div>
    <div id="fileSize"></div>
    <div id="fileType"></div>
    <div class="row">
      <input type="button" onclick="uploadFile()" value="Upload" />
    </div>
    <div id="progressNumber"></div>
  </form>

后端代码：

public ActionResult Upload() {
    HttpPostedFileBase file = Request.Files["fileToUpload"];
    file.SaveAs(Server.MapPath("/upload/")+file.FileName);
    return Content(file.FileName+"上传成功！");
}

链接: https://fly63.com/article/detial/226