仅顶部的 MouseOut 事件

Question

我正在尝试使用 mouseOut 事件处理程序，但我想限制当鼠标仅从顶部退出时触发事件——而不是从右侧、左侧或底部。

var executed = false;

function mouseoutHandler(e){
  window.removeEventListener("mouseout", mouseoutHandler, false);
    executed = true;
    document.getElementById(“element”).style.width = "300px";
}

function runOnce() {
  window.addEventListener("mouseout", mouseoutHandler, false);
};


runOnce();

我可以添加什么以使其仅在 mouseOut 来自元素顶部时触发？

Answer 1

您可以检查clientY是否小于元素的offsetTop 。
只有当鼠标光标离开顶部时，才会出现这种情况

 const myElement = document.getElementById('element'); var executed = false; const mouseoutHandler = (e) => { if(e.clientY <= myElement.offsetTop) { myElement.style.width = '100px'; executed = true; myElement.removeEventListener('mouseout', mouseoutHandler); } } myElement.addEventListener('mouseout', mouseoutHandler, false);

 body{height:100vh;display:flex;justify-content:center;align-items:center}#element{width:200px;height:100px;background:#333}

 <div id="element">&nbsp;</div>

---

编辑

IE 的非箭头函数

 var myElement = document.getElementById('element'); var executed = false; function mouseoutHandler(e) { if(e.clientY <= myElement.offsetTop) { myElement.style.width = '100px'; executed = true; myElement.removeEventListener('mouseout', mouseoutHandler); } } myElement.addEventListener('mouseout', mouseoutHandler, false);

 body{height:100vh;display:flex;justify-content:center;align-items:center}#element{width:200px;height:100px;background:#333}

 <div id="element">&nbsp;</div>