<p>显示 .xls, .xlsx, .csv 文件...</p>
<input type="file" accept=".csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel" ID="fileSelect" runat="server" />
<p>只显示 Excel (.xlsx) 文件...</p>
<input type="file" accept="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" ID="fileSelect" runat="server" />
<p>只显示 Excel (.xls) 文件...</p>
<input type="file" accept="application/vnd.ms-excel" ID="fileSelect" runat="server" />
<p>只显示图片.</p>
<input type="file" accept="image/*" ID="fileSelect" runat="server" />
<p>只显示文本文件...</p>
<input type="file" accept="text/plain" ID="fileSelect" runat="server" />
<p>只显示html文件.</p>
<input type="file" accept="text/html" ID="fileSelect" runat="server" />
<p>只显示 video 文件..</p>
<input type="file" accept="video/*" ID="fileSelect" runat="server" />
<p>只显示 audio 文件...</p>
<input type="file" accept="audio/*" ID="fileSelect" runat="server" />
<p>只显示 .WAV 文件...</p>
<input type="file" accept=".wav" ID="fileSelect" runat="server" />
<p>只显示 .PDF 文件...</p>
<input type="file" accept=".pdf" ID="fileSelect" runat="server" />
原文：https://blog.csdn.net/DosMing/article/details/77891560
后缀 MIME Type
.doc application/msword
.dot application/msword
.docx application/vnd.openxmlformats-officedocument.wordprocessingml.document
.dotx application/vnd.openxmlformats-officedocument.wordprocessingml.template
.docm application/vnd.ms-word.document.macroEnabled.12
.dotm application/vnd.ms-word.template.macroEnabled.12
.xls application/vnd.ms-excel
.xlt application/vnd.ms-excel
.xla application/vnd.ms-excel
.xlsx application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
.xltx application/vnd.openxmlformats-officedocument.spreadsheetml.template
.xlsm application/vnd.ms-excel.sheet.macroEnabled.12
.xltm application/vnd.ms-excel.template.macroEnabled.12
.xlam application/vnd.ms-excel.addin.macroEnabled.12
.xlsb application/vnd.ms-excel.sheet.binary.macroEnabled.12
.ppt application/vnd.ms-powerpoint
.pot application/vnd.ms-powerpoint
.pps application/vnd.ms-powerpoint
.ppa application/vnd.ms-powerpoint
.pptx application/vnd.openxmlformats-officedocument.presentationml.presentation
.potx application/vnd.openxmlformats-officedocument.presentationml.template
.ppsx application/vnd.openxmlformats-officedocument.presentationml.slideshow
.ppam application/vnd.ms-powerpoint.addin.macroEnabled.12
.pptm application/vnd.ms-powerpoint.presentation.macroEnabled.12
.potm application/vnd.ms-powerpoint.presentation.macroEnabled.12
.ppsm application/vnd.ms-powerpoint.slideshow.macroEnabled.12
原文：https://blog.csdn.net/xiaoranzhizhu/article/details/7047373