javascript - Jquery 文件拖放给我一个 "insecure operation"错误

Question

Note:

The answers & comments below reflect the state of legacy browsers in 2009. Now you can actually set the value of the file input element dynamically/programatically using JavaScript in 2017.

See the answer in this question for details as well as a demo:
How to set file input value programatically (i.e.: when drag-dropping files)?

我正在尝试使用 Jquery 实现上传图像的拖放功能。

这是我的代码:

上传.html

    <form id ="image_upload_form" action="" method="post" enctype="multipart/form-data">

        <input id="id_image" type="file" name="image">
        <input type="submit" value="Upload" />

    </form>

    <div id="drop_field"></div>

image_upload.js

$(document).ready(function() {
    var drop_field = $("#drop_field");
    drop_field.bind('dragover', file_drag_over);
    drop_field.bind('drop', file_select);   
});



function file_select(event) {
    event.stopPropagation();
    event.preventDefault();

    var file = event.originalEvent.dataTransfer.files [0];
    $("#id_image").val(file);
}



function file_drag_over(event) {
    event.stopPropagation();
    event.preventDefault();

    event.originalEvent.dataTransfer.dropEffect = "copy";    
}

一切正常，除了当我将图像文件拖放到字段上时，它给了我一个安全错误:

SecurityError: The operation is insecure.
    this.value = val;

我猜发生这种情况是因为我正在尝试修改文件输入字段的“值”属性。上传文件而不出现此安全错误的正确方法是什么？

谢谢!!

Answer 1

该错误是因为您正在尝试设置文件输入类型的值，由于安全原因，无法设置文件输入类型的值。

另请阅读this question和来自 MDN