Web Front-endJS TutorialHow to get dom elements in js? js method to find and get element objects through dom (code example)How to get dom elements in js? js method to find and get element objects through dom (code example)
How to get dom elements in js? This article will introduce to you the method of using JS to find and obtain element objects through DOM, so that you can understand what DOM in JS is and how to find and obtain elements through DOM. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
First of all, let’s briefly understand what is dom in js?
dom: HTML DOM, short for Document Object Model. When a web page is loaded, the browser will create the document object model of the page.
Usually, through JavaScript, we need to operate HTML elements. In order to do this, you must first find and obtain the element. Let's introduce three common methods to find and obtain element objects through dom in JavaScript:
1. Find and obtain elements by id: getElementById()
getElementById() method: Get the node element by ID. If the page contains multiple node objects with the same ID, only the first node object will be returned.
Syntax:
document.getElementById("元素的id");Code example: Click on the id="box" box and a pop-up window will appear, displaying the contents of the id="box" box
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
</head>
<body>
<div id="box" onclick="getValue()">我是测试代码</div>
<script>
function getValue(){
var x=document.getElementById("box")
alert(x.innerHTML)
}
</script>
</body>
</html>Rendering:
Note: There is no need to add "#" in front of the getElementById() brackets, because the method determines that the value in the brackets is the id of an element. value. This method returns a DOM object.
2. Find and obtain elements by tag name: getElementsByTagName()
getElementsByTagName() method: Find and obtain a set of elements by the tag name of the element Objects (get as many as there are), which returns a collection of objects with the specified tag name.
Grammar:
document.getElementsByClassName("元素的标签名");Code example:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
</head>
<body>
<p>Hello World!</p>
<div id="main">
<p>The DOM is very useful.</p>
<p>本例演示 <b>getElementsByTagName</b> 方法。</p>
</div>
<script>
var x=document.getElementById("main");
var y=x.getElementsByTagName("p");
document.write('id 为 "main" 的 div 中的第一段文本是：' + y[0].innerHTML);
</script>
</body>
</html>Effect picture:
3. Through class (Class) Find and get elements: getElementsByClassName()
getElementsByClassName() method: Find and get elements through the specified class (class) attribute value, and return the The collection of elements of the class name can be said to be a collection of objects.
Grammar:
document.getElementsByClassName("元素的class");Code example:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
</head>
<body>
<div id="main">
<p class="a">我是测试代码1</p>
<p class="a">我是测试代码2</p>
</div>
<script>
var x = document.getElementById("main");
var y = x.getElementsByClassName("a");
document.write('id 为 "main" 的 div 中的第一段文本是：' + y[0].innerHTML);
</script>
</body>
</html>Rendering:
Summary: The above is this article The entire content, I hope it will be helpful to everyone's study. For more related tutorials, please visit JavaScript Video Tutorial!
Related recommendations:
php public welfare training video tutorial
The above is the detailed content of How to get dom elements in js? js method to find and get element objects through dom (code example). For more information, please follow other related articles on the PHP Chinese website!
Javascript Data Types : Is there any difference between Browser and NodeJs?May 14, 2025 am 12:15 AMJavaScript core data types are consistent in browsers and Node.js, but are handled differently from the extra types. 1) The global object is window in the browser and global in Node.js. 2) Node.js' unique Buffer object, used to process binary data. 3) There are also differences in performance and time processing, and the code needs to be adjusted according to the environment.
JavaScript Comments: A Guide to Using // and /* */May 13, 2025 pm 03:49 PMJavaScriptusestwotypesofcomments:single-line(//)andmulti-line(//).1)Use//forquicknotesorsingle-lineexplanations.2)Use//forlongerexplanationsorcommentingoutblocksofcode.Commentsshouldexplainthe'why',notthe'what',andbeplacedabovetherelevantcodeforclari
Python vs. JavaScript: A Comparative Analysis for DevelopersMay 09, 2025 am 12:22 AMThe main difference between Python and JavaScript is the type system and application scenarios. 1. Python uses dynamic types, suitable for scientific computing and data analysis. 2. JavaScript adopts weak types and is widely used in front-end and full-stack development. The two have their own advantages in asynchronous programming and performance optimization, and should be decided according to project requirements when choosing.
Python vs. JavaScript: Choosing the Right Tool for the JobMay 08, 2025 am 12:10 AMWhether to choose Python or JavaScript depends on the project type: 1) Choose Python for data science and automation tasks; 2) Choose JavaScript for front-end and full-stack development. Python is favored for its powerful library in data processing and automation, while JavaScript is indispensable for its advantages in web interaction and full-stack development.
Python and JavaScript: Understanding the Strengths of EachMay 06, 2025 am 12:15 AMPython and JavaScript each have their own advantages, and the choice depends on project needs and personal preferences. 1. Python is easy to learn, with concise syntax, suitable for data science and back-end development, but has a slow execution speed. 2. JavaScript is everywhere in front-end development and has strong asynchronous programming capabilities. Node.js makes it suitable for full-stack development, but the syntax may be complex and error-prone.
JavaScript's Core: Is It Built on C or C ?May 05, 2025 am 12:07 AMJavaScriptisnotbuiltonCorC ;it'saninterpretedlanguagethatrunsonenginesoftenwritteninC .1)JavaScriptwasdesignedasalightweight,interpretedlanguageforwebbrowsers.2)EnginesevolvedfromsimpleinterpreterstoJITcompilers,typicallyinC ,improvingperformance.
JavaScript Applications: From Front-End to Back-EndMay 04, 2025 am 12:12 AMJavaScript can be used for front-end and back-end development. The front-end enhances the user experience through DOM operations, and the back-end handles server tasks through Node.js. 1. Front-end example: Change the content of the web page text. 2. Backend example: Create a Node.js server.
Python vs. JavaScript: Which Language Should You Learn?May 03, 2025 am 12:10 AMChoosing Python or JavaScript should be based on career development, learning curve and ecosystem: 1) Career development: Python is suitable for data science and back-end development, while JavaScript is suitable for front-end and full-stack development. 2) Learning curve: Python syntax is concise and suitable for beginners; JavaScript syntax is flexible. 3) Ecosystem: Python has rich scientific computing libraries, and JavaScript has a powerful front-end framework.
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.
MinGW - Minimalist GNU for Windows
This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.
Zend Studio 13.0.1
Powerful PHP integrated development environment
ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment
mPDF
mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),
