僅頂部的 MouseOut 事件

Question

我正在嘗試使用 mouseOut 事件處理程序，但我想限制當鼠標僅從頂部退出時觸發事件——而不是從右側、左側或底部。

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僅在 mouseOut 來自元素頂部時觸發？

Answer 1

您可以檢查clientY是否小於元素的offsetTop 。
只有當鼠標光標離開頂部時，才會出現這種情況

 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>

---

編輯

IE 的非箭頭函數

 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>