文件上传时只接收指定的文件类型

Valid Accept Types:

For CSV files (.csv), use: 

<input type="file" accept=".csv" />

For Excel Files 2003-2007 (.xls), use: 

<input type="file" accept="application/vnd.ms-excel" />

For Excel Files 2010 (.xlsx), use: 

<input type="file" accept="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" />

For Text Files (.txt) use: 

<input type="file" accept="text/plain" />

For Image Files (.png/.jpg/etc), use: 

<input type="file" accept="image/*" />

For HTML Files (.htm,.html), use:

<input type="file" accept="text/html" />

For Video Files (.avi, .mpg, .mpeg, .mp4), use:

<input type="file" accept="video/*" />

For Audio Files (.mp3, .wav, etc), use:

<input type="file" accept="audio/*" />

For PDF Files, use:

<input type="file" accept=".pdf" /> 

DEMO:
http://jsfiddle.net/dirtyd77/LzLcZ/144/

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NOTE:

If you are trying to display Excel CSV files (.csv), do NOT use:

• text/csv
• application/csv
• text/comma-separated-values (works in Opera only).

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If you are trying to display a particular file type (for example, a WAV or PDF), then this will almost always work...

 <input type="file" accept=".FILETYPE" />

原文地址：http://blog.youkuaiyun.com/hanshileiai/article/details/44702923