In the absence of the parent div, the child div is printed as follows

Mouseover:

  1. Div1,
  2. Div2, div1,
  3. Div1,
  4. Div2, div1

The child div is triggered first

Mouseenter:

  • div2
  • div2
  • div2

Div1 does not trigger

The test code

<! DOCTYPEhtml>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="Width = device - width, initial - scale = 1.0">
    <title>Document</title>

    <style>
        .div1 {
            width: 200px;
            height: 200px;
            background-color: aqua;
            position: relative;
            left: 0;
        }

        .div2 {
            width: 100px;
            height: 100px;
            background-color: red;
            position: absolute;
            left: 200px;
        }
    </style>
</head>

<body>

    <div class="div1">
        <div class="div2"></div>
    </div>

    <script>
        const div1 = document.getElementsByClassName("div1") [0]
        const div2 = document.getElementsByClassName("div2") [0]
        div1.addEventListener("mouseenter".function () {
            console.log("div1")
        })
        div2.addEventListener("mouseenter".function () {
            console.log("div2")})</script>

</body>

</html>
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