<form> <input type="file" name="upfile"> <button id="upButton" type="button">送信</button> </form> let $upfile = $('input[name="upfile"]'); let fd = new FormData(); fd.append("upfile", $upfile.prop('files')[0]); $('#upButton').on('click', function () { $.ajax({ url:'index.php', type:'post', data: fd, processData: false, contentType: false, cache: false, }).done(function (data) { // 成功時の処理 }).fail(fu