accept only csv html code example
Example 1: html input file type csv
<input id="fileSelect" type="file" accept=".csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel" />
Example 2: input type file csv only
<input type="file" id="img" name="img" accept=".csv, application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel">