getElementsByClassName

https://developer.mozilla.org/fr/docs/Web/API/Document/getElementsByClassName

Sélectionner des éléments par leurs “class”

<body>
    <div>
        <p>hello word1</p>
        <p class="test">hello word2</p>
        <p >hello word3</p>
        <p>hello word4</p>
    </div>
    <script>
        var test=document.getElementsByClassName("test");
        console.log(test); //HTMLCollection[1]

        var testTarget=document.getElementsByClassName("test")[0];//here , this element is target
        console.log(testTarget); //<p class="test">hello word2</p>
    </script>
</body>