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