html：
<input type="file" name="uploadFile" id="uploadFile">
jq:
$("#uploadFile").on("change", function() {
var formData = new Formdata (); // create a form of the data type
formData.append ($ ( "# uploadFile") [0] .files); // get the data uploaded file
$.ajax({
"url": "",
"type": "",
"ProcessData": false, // convert the data to an object, do not process data, so processData: false
"ContentType": false, // do not set the data type
"XhrFields": {// This automatically sends a cookie to the browser in the background when requested
withCredentials: true
}，
"data": formData,
success: function(data) {
console.log(data)
},
error: function(data) {
}
})
})