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Selecting DOM (Document Object Model) elements is a fundamental aspect of web development with JavaScript. It allows developers to interact with and manipulate elements on a webpage dynamically. Proper selection of elements is crucial for tasks such as updating content, adding event listeners, or modifying styles.
Below are the approaches to select DOM elements in JavaScript:
Using getElementByIdThis method selects a single element by its unique ID attribute.
Syntax:document.getElementById('id')Example:
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,
initial-scale=1.0">
<title>getElementById Example</title>
</head>
<body>
<h1 id="gfg">GeeksForGeeks</h1>
<script>
// styling the h1 tag
const element = document.getElementById('gfg');
element.style.color = "green";
element.style.textAlign = "center";
element.style.margin = "30px";
element.style.fontSize = "30px";
</script>
</body>
</html>
Output:
 Output Using getElementsByClassNameThis method selects elements based on their class attribute. It returns a collection of elements with the specified class name.
Syntax: document.getElementsByClassName('class')Example:
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, initial-scale=1.0">
<title>getElementsByClassName Example</title>
</head>
<body>
<h1 class="selector">GeeksForGeeks</h1>
<h2 class="selector">DOM selector in JavaScript</h2>
<script>
const elements =
documSizeent.getElementsByClassName('selector');
elements[0].style.color = "green";
elements[1].style.color = "red";
elements[0].style.textAlign = "center";
elements[1].style.textAlign = "center";
elements[0].style.marginTop = "60px";
</script>
</body>
</html>
Output:
 Output Using getElementsByTagNameThis method selects elements based on their tag name. It returns a collection of elements with the specified tag name.
Syntax:document.getElementsByTagName('tag')Example:
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, initial-scale=1.0">
<title>getElementsByTagName Example</title>
</head>
<body>
<p>Thanks for visiting GFG</p>
<p>This is showing how to select DOM element using tag name</p>
<script>
const paragraphs = document.getElementsByTagName('p');
paragraphs[0].style.color = "green";
paragraphs[1].style.color = "blue";
paragraphs[0].style.fontSize = "25px";
paragraphs[0].style.textAlign = "center";
paragraphs[1].style.textAlign = "center";
paragraphs[0].style.marginTop = "60px";
</script>
</body>
</html>
Output:
 Output Using querySelectorThis method selects the first element that matches a specified CSS selector. It returns only one element.
Syntax:document.querySelector('selector')Example:
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width,
initial-scale=1.0">
<title>querySelector Example</title>
</head>
<body>
<div class="gfg">GeeksForGeeks</div>
<script>
const element =
document.querySelector('.gfg');
element.style.color = "green";
element.style.textAlign = "center";
element.style.margin = "30px";
element.style.fontSize = "30px";
</script>
</body>
</html>
Output:
 Output Using querySelectorAllSimilar to querySelector, but it returns a NodeList containing all elements that match the specified CSS selector.
Syntax:document.querySelectorAll('selector')Example:
HTML
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, initial-scale=1.0">
<title>querySelectorAll Example</title>
</head>
<body>
<h1 class="selector">GeeksForGeeks</h1>
<p class="selector">
This is showing how to select DOM element
using tag name
</p>
<script>
const elements = document.querySelectorAll('.selector');
elements[0].style.color = "green";
elements[1].style.color = "red";
elements[0].style.textAlign = "center";
elements[1].style.textAlign = "center";
elements[0].style.marginTop = "60px";
</script>
</body>
</html>
Output:
 Output
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