<input type="file" name="file" id="file">
<button id="upload" onClick="upload()">upload</button>

var bytesPerPiece = 1024 * 1024; // 每個檔案切片大小定為1MB .
        var totalPieces;
        //傳送請求
        function upload() {
            var blob = document.getElementById("file").files[0];
            var start = 0;
            var end;
            var index = 0;
            var filesize = blob.size;
            var filename = blob.name;

            //計算檔案切片總數
            totalPieces = Math.ceil(filesize / bytesPerPiece);
            while(start < filesize) {
                end = start + bytesPerPiece;
                if(end > filesize) {
                    end = filesize;
                }

                var chunk = blob.slice(start,end);//切割檔案    
                var sliceIndex= blob.name + index;
                var formData = new FormData();
                formData.append("file", chunk, filename);
                $.ajax({
                    url: 'http://localhost:9999/test.php',
                    type: 'POST',
                    cache: false,
                    data: formData,
                    processData: false,
                    contentType: false,
                }).done(function(res){ 

                }).fail(function(res) {

                });
                start = end;
                index++;
            }
        }