HTML Input="file" Accept Attribute File Type (CSV)

Well this is embarrassing... I found the solution I was looking for and it couldn't be simpler. I used the following code to get the desired result.

<input id="fileSelect" type="file" accept=".csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel" />  

Valid Accept Types:

For CSV files (.csv), use:

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

For Excel Files 97-2003 (.xls), use:

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

For Excel Files 2007+ (.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/

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).

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" />

These days you can just use the file extension

<input type="file" ID="fileSelect" accept=".xlsx, .xls, .csv"/>

Dom this attribute is very old and not accepted in modern browsers as far as I know, But here is an alternative to it, Try this

<script type="text/javascript" language="javascript">
function checkfile(sender) {
    var validExts = new Array(".xlsx", ".xls", ".csv");
    var fileExt = sender.value;
    fileExt = fileExt.substring(fileExt.lastIndexOf('.'));
    if (validExts.indexOf(fileExt) < 0) {
      alert("Invalid file selected, valid files are of " +
               validExts.toString() + " types.");
      return false;
    }
    else return true;
}
</script>

<input type="file" id="file" onchange="checkfile(this);" />

I guess it'll help you of course you can change this script according to your needs.