<input type="file" accept="image/*" />
accept表示可以上传文件类型，image表示图片，*表示所有支持的格式。VUE不好用
accept可以指定如下信息：
*.3gpp | audio/3gpp, video/3gpp | 3GPP Audio/Video |
*.ac3 | audio/ac3 | AC3 Audio |
*.asf | allpication/vnd.ms-asf | Advanced Streaming Format |
*.au | audio/basic | AU Audio |
*.css | text/css | Cascading Style Sheets |
*.csv | text/csv | Comma Separated Values |
*.doc | application/msword | MS Word Document |
*.docx | application/vnd.openxmlformats-officedocument.wordprocessingml.document | MS Word Document |
*.dot | application/msword | MS Word Template |
*.dotx | application/vnd.openxmlformats-officedocument.wordprocessingml.template | Document Type Definition |
*.dtd | application/xml-dtd | Document Type Definition |
*.dwg | image/vnd.dwg | AutoCAD Drawing Database |
*.dxf | image/vnd.dxf | AutoCAD Drawing Interchange Format |
*.gif | image/gif | Graphic Interchange Format |
*.htm | text/html | HyperText Markup Language |
*.html | text/html | HyperText Markup Language |
*.jp2 | image/jp2 | JPEG-2000 |
*.jpe | image/jpeg | JPEG |
*.jpeg | image/jpeg | JPEG |
*.jpg | image/jpeg | JPEG |
*.js | text/javascript, application/javascript | JavaScript |
*.json | application/json | JavaScript Object Notation |
*.mp2 | audio/mpeg, video/mpeg | MPEG Audio/Video Stream, Layer II |
*.mp3 | audio/mpeg | MPEG Audio Stream, Layer III |
*.mp4 | audio/mp4, video/mp4 | MPEG-4 Audio/Video |
*.mpeg | video/mpeg | MPEG Video Stream, Layer II |
*.mpg | video/mpeg | MPEG Video Stream, Layer II |
*.mpp | application/vnd.ms-project | MS Project Project |
*.ogg | application/ogg, audio/ogg | Ogg Vorbis |
application/pdf | Portable Document Format | |
*.png | image/png | Portable Network Graphics |
*.pot | application/vnd.ms-powerpoint | MS PowerPoint Template |
*.potx | application/vnd.openxmlformats-officedocument.presentationml.template | MS PowerPoint Template |
*.pps | application/vnd.ms-powerpoint | MS PowerPoint Slideshow |
*.ppsx | application/vnd.openxmlformats-officedocument.presentationml.slideshow | MS PowerPoint Slideshow |
*.ppt | application/vnd.ms-powerpoint | MS PowerPoint Presentation |
*.pptx | application/vnd.openxmlformats-officedocument.presentationml.presentation | MS PowerPoint Presentation |
*.sldx | application/vnd.openxmlformats-officedocument.presentationml.slide | |
*.rtf | application/rtf, text/rtf | Rich Text Format |
*.svf | image/vnd.svf | Simple Vector Format |
*.tif | image/tiff | Tagged Image Format File |
*.tiff | image/tiff | Tagged Image Format File |
*.txt | text/plain | Plain Text |
*.wdb | application/vnd.ms-works | MS Works Database |
*.wps | application/vnd.ms-works | Works Text Document |
*.xhtml | application/xhtml+xml | Extensible HyperText Markup Language |
*.xlc | application/vnd.ms-excel | MS Excel Chart |
*.xlm | application/vnd.ms-excel | MS Excel Macro |
*.xls | application/vnd.ms-excel | MS Excel Spreadsheet |
*.xlsx | application/vnd.openxmlformats-officedocument.spreadsheetml.sheet | MS Excel Spreadsheet |
*.xlsm | application/vnd.ms-excel.addin.macroEnabled.12 | |
*.xlsb | application/vnd.ms-excel.sheet.binary.macroEnabled.12 | |
*.xlt | application/vnd.ms-excel | MS Excel Template |
*.xltx | application/vnd.openxmlformats-officedocument.spreadsheetml.template | MS Excel Template |
*.xlw | application/vnd.ms-excel | MS Excel Workspace |
*.xml | text/xml, application/xml | Extensible Markup Language |
*.zip | aplication/zip | Compressed Archive |