关键技术
1、FormData
2、XMLHttpRequest
先在页面布局如下结构
<form > <label for="fileToUpload">Select a File to Upload</label> <input type="file" name="fileToUpload" /> </div> <div ></div> <div ></div> <div ></div> <div class="row"> <input type="button" onclick="uploadFile()" value="Upload" /> </div> <div ></div> </form>
以下是javascript脚本
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", "/file-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."); }
服务器端用node,当然得先添加express依赖
/* @express 4.X
express install
npm install
npm install multer --save
var multer = require ( 'multer' );
app.use(multer({ dest: './file-upload/' }));
*/
var express = require("express"), app = express(), server = require("http").createServer(app), fs = require("fs"); app.listen(6688); app.use(express.bodyParser({uploadDir: './upload-file'})); app.use(express.static(__dirname + '/static')); app.get('/', function(req, res) { fs.readFile(__dirname+'/index.html', function(err, data) { if (err) { res.writeHeader(500); res.end('index.html error'); } res.writeHeader(200); res.end(data); }) }); app.post('/file-upload', function(req, res) { res.send('ok'); })
是不是很简单?