官术网_书友最值得收藏!

DOM

The DOM is what is used to describe the structure of an HTML or XML page. It creates a tree-like structure that provides us with the ability to do everything from creating, reading, updating, and deleting nodes to traversing the tree and many more features, all within JavaScript. Let's consider the following HTML page:

<!DOCTYPE html>
<html lang="en">
<head>
<title>DOM Example</title>
</head>
<body>
<div>
<p>I love JavaScript!</p>
<p>Here's a list of my favourite frameworks:</p>
<ul>
<li>Vue.js</li>
<li>Angular</li>
<li>React</li>
</ul>
</div>

<script src="app.js"></script>
</body>
</html>

We're able to look at the HTML and see that we have one div, two p, one ul, and li tags. The browser parses this HTML and produces the DOM Tree, which at a high level looks similar to this:

We can then interact with the DOM to get access to these elements by TagName using document.getElementsByTagName(), returning a HTML collection. If we wanted to map over these collection objects, we could create an array of these elements using Array.from. The following is an example:

const paragraphs = Array.from(document.getElementsByTagName('p'));
const listItems = Array.from(document.getElementsByTagName('li'));

paragraphs.map(p => console.log(p.innerHTML));
listItems.map(li => console.log(li.innerHTML));

This should then log the innerHTML of each item to the console inside of our array(s), thus showing how we can access items inside of the DOM:

主站蜘蛛池模板: 大安市| 北海市| 六盘水市| 原平市| 武鸣县| 泗洪县| 马边| 昭平县| 潞城市| 青海省| 佛冈县| 开鲁县| 泰兴市| 固镇县| 菏泽市| 县级市| 阿图什市| 霍邱县| 齐河县| 渝北区| 措美县| 乌兰察布市| 乌什县| 巴南区| 南江县| 丰宁| 本溪| 福泉市| 红安县| 灵璧县| 新丰县| 萍乡市| 龙江县| 金山区| 凉城县| 威信县| 日照市| 安徽省| 东乡县| 宁安市| 和田市|