如何实现文件拖拽上传功能？拖拽上传句柄包含什么信息？

<div class="box">拖拽文件到这个位置</div>
<script>
    let drop_box = document.querySelector(".box");
    drop_box.addEventListener("dragenter", function () {
        console.log("进入"); // 只进入一次
    });
    drop_box.addEventListener("dragover", function (e) {
        e.preventDefault();
        console.log("over"); // 连续over
    });
</script>

drop_box.addEventListener(
    "drop",
    function (e) {
        e.preventDefault();
        var _files = e.dataTransfer.files; // 这个就相当于文件上传组件
        // doUpload(_files);
    },
    false
);

function doUpload(_files) {
    for (let i = 0; i < _files.length; i++) {
        var data2 = new FormData();
        data2.append("file", _files[i]);
        $.ajax({
            async: true,
            url: "upload.php",
            type: "POST",
            cache: false,
            processData: false,
            contentType: false,
            data: data2,
            timeout: 60000,
            success: function (json) {
                console.log(json);
            },
            error: function (json) { },
        });
    }
}

<script src="https://cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
<style>
    .box {
        width: 300px;
        height: 80px;
        border: 1px solid #ccc;
        line-height: 80px;
        text-align: center;
        color: #ccc;
    }
</style>
<div class="box">拖拽文件到这个位置</div>
<script>
    let drop_box = document.querySelector(".box");
    drop_box.addEventListener("dragstart", function (e) {
        e.preventDefault();
        console.log("进入"); // 只进入一次
    });
    drop_box.addEventListener("dragenter", function (e) {
        e.preventDefault();
        console.log("进入"); // 只进入一次
    });
    drop_box.addEventListener("dragover", function (e) {
        e.preventDefault();
        console.log("over"); // 连续over
    });
    drop_box.addEventListener(
        "drop",
        function (e) {
            e.stopPropagation();               // firefox必须加上这句话
            e.preventDefault();
            var _files = e.dataTransfer.files; // 这个就相当于文件上传组件
            doUpload(_files);
        },
        false
    );
    function doUpload(_files) {
        for (let i = 0; i < _files.length; i++) {
            var data2 = new FormData();
            data2.append("file", _files[i]);
            $.ajax({
                async: true,
                url: "upload.php",
                type: "POST",
                cache: false,
                processData: false,
                contentType: false,
                data: data2,
                timeout: 60000,
                success: function (json) {
                    console.log(json);
                },
                error: function (json) { },
            });
        }
    }
</script>

e.stopPropagation();               // firefox必须加上这句话
e.preventDefault();