contentType: false // 告诉 jQuery 别设置内容类型

var fd = new FormData(document.getElementById("fileinfo"));
fd.append("CustomField", "This is some extra data");
$.ajax({
  url: "stash.php",
  type: "POST",
  data: fd,
  processData: false,  // tell jQuery not to process the data
  contentType: false   // tell jQuery not to set contentType
});

https://developer.mozilla.org/en-US/d...

是不是可以加上jQuery的配置：

$('#jquery').submit(function () {
    var formData;

    formData = new FormData();
    formData.append('file', $('input[name=file]', this).get(0).files[0]);

    $.ajax({
        url: '/',
        contentType:"multipart/form-data",
        data: formData,
        processData: false,
        type: 'POST'
    });
    
    return false;
});