JavaScript Dom0 Dom1

时间：2023-03-26 23:54:32

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DOM 0写法

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<body>

    <table border="1" width="300px">

        <tr onmousemove="t1(0);" onmouseout="t2(0)"><td>1</td><td>2</td><td>3</td></tr>

        <tr onmousemove="t1(1);" onmouseout="t2(1)"><td>1</td><td>2</td><td>3</td></tr>

        <tr onmousemove="t1(2);" onmouseout="t2(2)"><td>1</td><td>2</td><td>3</td></tr>

    </table>

    <script>

        //DOM 0实现的效果

        function t1(n){

            var mytrs = document.getElementsByTagName('tr')[n];

            console.log(mytrs);

            mytrs.style.backgroundColor = "red";

        }

        function t2(n){

            var mytrs = document.getElementsByTagName('tr')[n];

            console.log(mytrs);

            mytrs.style.backgroundColor = "";

        }

    </script>

</body>

</html>

Demo

Demo

DOM 1写法

<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>Title</title>

</head>

<style>

    .c1{

        background-color: cadetblue;

        width: 300px;

    }

</style>

<body>

    <div class="c1">

        <table border="1" width="300px">

        <tr><td>1</td><td>2</td><td>3</td></tr>

        <tr><td>1</td><td>2</td><td>3</td></tr>

        <tr><td>1</td><td>2</td><td>3</td></tr>

    </table>

    </div>

    <script>

        //DOM 1实现的效果

        var myTrs = document.getElementsByTagName("tr");

        var len = myTrs.length;

        for(var i=0;i<len;i++){

            myTrs[i].onmouseover = function(){  //绑定事件

               this.style.backgroundColor = "red"; //谁调用这个函数,这个this就指向谁

            }

            myTrs[i].onmouseout = function(){

                this.style.backgroundColor = "";

            }

        }

    </script>

</body>

</html>

Demo

第一种非常低效，每次都要在标签上绑定。

第二种相对高效一点，首先获取DOM对象，然后一次绑定。

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