在 addEventListener 或 element.on* 附加的事件处理程序中“返回 false”

发布于 2024-09-13 18:49:03 字数 574 浏览 3 评论 0原文

好吧，让我们先解决这个问题。是的，我想隐藏上下文菜单。不，我并不是试图阻止有人从我的页面上窃取内容。其预期用途是浏览器内游戏的输入，并且仅限于网页上的特定区域。

从意识形态转向技术......

var mouse_input = function (evt) {
    // ...
    return false;
}

document.onmousedown = mouse_input; // successful at preventing the menu.
document.addEventListener('mousedown', mouse_input, true); // unsuccessful

有人可以向我解释为什么 addEventListener 版本无法阻止上下文菜单触发吗？我在 Safari 的 Web Inspector 中看到的唯一区别是 document.onmousedown 有一个 isAttribute值为 true，而 addEventListener 版本的值为 false。

原文

Right let’s get this out the way first. Yes, I want to hide the context menu. No, I’m not trying to prevent someone lifting content off my page. Its intended use is input for an in-browser game and it will be limited to a specific area on the webpage.

Moving from the ideological to the technical...

var mouse_input = function (evt) {
    // ...
    return false;
}

document.onmousedown = mouse_input; // successful at preventing the menu.
document.addEventListener('mousedown', mouse_input, true); // unsuccessful

Could someone explain to me why the addEventListener version is unable to stop the context menu from firing? The only difference I was able to see in Safari's Web Inspector was that document.onmousedown had a isAttribute value that was true whilst the addEventListener version had the same value as false.

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一紙繁鸢 2024-09-20 18:49:03

于是，我徒劳的寻找突然变得富有成效。

var mouse_input = function (evt) {
    evt.preventDefault();
}

document.addEventListener('contextmenu', mouse_input, false);

适用于 Safari、Firefox、Opera。 preventDefault() 阻止常见操作的发生。我必须更改监听的事件以适应 Safari，无论如何，它更符合逻辑。更多信息：实现 EventListener 不应返回值，因此 return false 无效。

So my unfruitful search suddenly became fruitful.

var mouse_input = function (evt) {
    evt.preventDefault();
}

document.addEventListener('contextmenu', mouse_input, false);

Works for Safari, Firefox, Opera. preventDefault() stops the usual actions from happening. I had to change the event that was listened for to accommodate for Safari and it is more logical anyway. Further information: functions that implement EventListener shouldn’t return values so return false had no effect.

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