以HTML5的文件上传API
如下demo代码在.html文件打开即可：
!DOCTYPE html> <html lang="zh_cn"> <head> <meta charset="UTF-8"> <title>HTML5文件上传FileReader API</title> </head> <body> <!--一个能上传多媒体文件的表单--> <input type="file" id="upload-file" multiple /> <!--显示图片的地方--> <div id="destination"></div> <script> document.getElementById('upload-file').addEventListener('change', function() { var file; var destination = document.getElementById('destination'); destination.innerHTML = '';//每次清空内容 // 循环用户多选的文件 for(var x = 0, xlen = this.files.length; x < xlen; x++) { file = this.files[x]; console.log(file); if(file.type.indexOf('image') != -1) { // 非常简单的交验，判断文件是否是图片 var reader = new FileReader();//文件预览对象 reader.readAsDataURL(file);//设置要预览的文件 reader.onload = function(e) {//监听文件加载完成事件 var img = new Image();//创键预览图片 img.src = e.target.result; //把预览图片的src设置为e.target.result属性。返回预览文件的二进制内存数据 destination.appendChild(img);//在把每张图片，放到预览区域 }; } } }); </script> </body> </html>
一、input:file属性
属性值有以下几个比较常用：
accept：表示可以选择的文件MIME类型，多个MIME类型用英文逗号分开，常用的MIME类型见下表。
multiple：是否可以选择多个文件，多个文件时其value值为第一个文件的虚拟路径。
1、accept
只能选择png和gif图片
<input id="fileId1" type="file" accept="image/png,image/gif" name="file" />2、multiple
多选文件上传
<input id="fileId2" type="file" multiple="multiple" name="file" />3、常用MIME类型
后缀名 MIME名称
*.3gpp audio/3gpp, video/3gpp
*.ac3 audio/ac3
*.asf allpication/vnd.ms-asf
*.au audio/basic
*.css text/css
*.csv text/csv
*.doc application/msword
*.dot application/msword
*.dtd application/xml-dtd
*.dwg image/vnd.dwg
*.dxf image/vnd.dxf
*.gif image/gif
*.htm text/html
*.html text/html
*.jp2 image/jp2
*.jpe image/jpeg
*.jpeg image/jpeg
*.jpg image/jpeg
*.js text/javascript, application/javascript
*.json application/json
*.mp2 audio/mpeg, video/mpeg
*.mp3 audio/mpeg
*.mp4 audio/mp4, video/mp4
*.mpeg video/mpeg
*.mpg video/mpeg
*.mpp application/vnd.ms-project
*.ogg application/ogg, audio/ogg
*.pdf application/pdf
*.png image/png
*.pot application/vnd.ms-powerpoint
*.pps application/vnd.ms-powerpoint
*.ppt application/vnd.ms-powerpoint
*.rtf application/rtf, text/rtf
*.svf image/vnd.svf
*.tif image/tiff
*.tiff image/tiff
*.txt text/plain
*.wdb application/vnd.ms-works
*.wps application/vnd.ms-works
*.xhtml application/xhtml+xml
*.xlc application/vnd.ms-excel
*.xlm application/vnd.ms-