How to upload a file using an ajax call in flask

To answer your question…

HTML:

<form id="upload-file" method="post" enctype="multipart/form-data">
    <fieldset>
        <label for="file">Select a file</label>
        <input name="file" type="file">
    </fieldset>
    <fieldset>
        <button id="upload-file-btn" type="button">Upload</button>
    </fieldset>
</form>

JavaScript:

$(function() {
    $('#upload-file-btn').click(function() {
        var form_data = new FormData($('#upload-file')[0]);
        $.ajax({
            type: 'POST',
            url: '/uploadajax',
            data: form_data,
            contentType: false,
            cache: false,
            processData: false,
            success: function(data) {
                console.log('Success!');
            },
        });
    });
});

Now in your flask’s endpoint view function, you can access the file’s data via flask.request.files.

On a side note, forms are not tabular data, therefore they do not belong in a table. Instead, you should resort to an unordered list, or a definition list.