带有event.preventDefault的HTML [英] HTML with event.preventDefault
问题描述
如果html文档被禁用。 (不滚动...)
document.ontouchmove = function(event){event.preventDefault(); }
我可以选择性地在html文档中启用元素吗?如div,跨越
我应该用什么javascript来做到这一点?
这是一个相当不好的解决方案。
更改您的 touchmove
处理程序,如下所示:
document.ontouchmove = function(event){
if(!event.elementIsEnabled){
event.preventDefault();
}
};
然后对于您要启用的元素:
element.ontouchmove = function(event){
event.elementIsEnabled = true;
};
这是因为:
touchmove
事件时,这两个事件处理程序将在冒泡阶段处理该事件。这意味着元素 touchmove
处理程序首先触发,因为它最接近事件源。 当两个事件处理程序处理相同的事件,他们收到相同的事件对象。
因此,元素 touchmove
处理程序只是在事件对象上设置一个自定义属性,然后文档 touchmove
处理程序检查该定制属性以确定是否应该阻止默认操作。
If the html document is disabled. (no scrolling...)
document.ontouchmove = function(event){ event.preventDefault(); }
Can I selectively enabled elements in the html document? such as a div, span What javascript should I use to do that?
Here’s a fairly hacky solution.
Change your touchmove
handler as follows:
document.ontouchmove = function (event) {
if (!event.elementIsEnabled) {
event.preventDefault();
}
};
Then for an element that you want to enable:
element.ontouchmove = function (event) {
event.elementIsEnabled = true;
};
This works because:
- When a
touchmove
event is fired on the element, both of these event handlers handle the event in the bubbling phase. This means that the elementtouchmove
handler fires first, because it is closest to the source of the event. - When two event handlers handle the same event, they receive the same event object.
- You’re allowed to set your own arbitrary properties on an event object.
So, the element touchmove
handler just sets a custom property on the event object, and then the document touchmove
handler checks for that custom property to determine whether the default action should be prevented.
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