the usual file upload is to select a file in the system pop-up window,

then click the open button to upload the file directly,

now we have a requirement that after the operation in the system pop-up window is completed, the upload will not be carried out, but the list of files to be uploaded will be displayed.
it will not be uploaded until a button to start uploading is clicked.

the question now is how to control whether the file is uploaded or not.