表单提交前弹出窗口，点确认后提交，否则关闭弹出窗口不提交表单。此功能如何实现？

[yichangle]

如题，用popup加表单验证功能无法实现，因为是验证是同步执行，没机会响应用户点击popup上按钮的结果。

[wang0618]

可以使用锁机制来将popup变成同步的:

from pywebio import start_server
from pywebio.output import *

import threading


def confirm(title, content=None, timeout=None):
    """Show a confirm model.

    :param str title: Model title.
    :param list/put_xxx() content: Model content.
    :param None/float timeout:
    :return: Return `True` when the "CONFIRM" button is clicked, return `False` when the "CANCEL" button is clicked,
        return `None` when a timeout is given and the operation times out.
    """
    if not isinstance(content, list):
        content = [content]

    event = threading.Event()
    result = None

    def onclick(val):
        nonlocal result
        result = val
        event.set()

    content.append(put_buttons([
        {'label': 'CONFIRM', 'value': True},
        {'label': 'CANCEL', 'value': False, 'color': 'danger'},
    ], onclick=onclick))
    popup(title=title, content=content, closable=False)

    event.wait(timeout=timeout)
    close_popup()
    return result


def main():
    res = confirm('Confirm', 'You have 5 seconds to make s choice', timeout=5)
    put_text("Your choice is:", res)


start_server(main, port=8080, debug=True)

[yichangle]

谢谢！效果非常棒。