input file控件限制上传文件类型

　　网页上添加一个input file HTML控件：

<input id="File1" type="file" />

　　默认是这样的，所有文件类型都会显示出来，如果想限制它只显示我们设定的文件类型呢，比如“word“,”excel“,”pdf“文件　

　　解决办法是可以给它添加一个accept属性，比如：

<input id="File1" type="file"  accept=".xls,.doc,.txt,.pdf"  />

　　这样选择的时候默认会显示为这样：

文件选择框内只显示出你自定义文件类型的文件，也还比较方便。

But,这只是最简单的掩人耳目的做法，还是能选择其它文件类型：

所以，如果要做到真正意义上限制类型做法（其实这种算不上限制，只是把你要的文件类型默认显示出来而已，并不是说不能选择其它的），还是要通过js或者后台来控制。

附支持的文件类型：

*.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
*.dot	application/msword	MS Word Template
*.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
*.pdf	application/pdf	Portable Document Format
*.png	image/png	Portable Network Graphics
*.pot	application/vnd.ms-powerpoint	MS PowerPoint Template
*.pps	application/vnd.ms-powerpoint	MS PowerPoint Slideshow
*.ppt	application/vnd.ms-powerpoint	MS PowerPoint Presentation
*.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
*.xlt	application/vnd.ms-excel	MS Excel Template
*.xlw	application/vnd.ms-excel	MS Excel Workspace
*.xml	text/xml， application/xml	Extensible Markup Language
*.zip	aplication/zip	Compressed Archive