ajax上传文件

<input type="button" value="提交"  onclick="submit_upload(this)"></form>；

   function submit_upload(target){
        var formData = new FormData(target.form);
        $.ajax({  
            url: "/users/upload_receipt" ,
            type: 'POST',  
            data: formData,  
            async: false,  
            cache: false,  
            contentType: false,  
            processData: false,  
            success: function (data) {
                let obj = JSON.parse(data)
                if(obj.msg == "回执上传成功") {
                    window.location.reload();
                } else {
                    alert(obj.msg)
                }
            },  
            error: function (data) {
                alert(`上传失败`);  
            }  
        });  
    }