Browser APIs and DOM Manipulation in JavaScript

Browser APIs are a set of interfaces and methods provided by web browsers, which can be used by web developers to interact with the browser and the underlying operating system. Some examples of browser APIs include the Document Object Model (DOM), the XMLHttpRequest (XHR) object, the fetch() function, and the Web Audio API.

The DOM is a programming interface for web documents. It represents the page so that programs can change the document structure, style, and content. With the DOM, JavaScript can access and manipulate the HTML and CSS of a web page.

DOM manipulation involves accessing or modifying the elements of an HTML page using JavaScript. To manipulate the DOM, you first need to select the element you want to work with. You can do this using a variety of methods, such as document.getElementById(), document.querySelector(), or document.querySelectorAll(). Once you have selected the element, you can modify its properties, such as its innerHTML, style, or classList.

Here's an example of using JavaScript to manipulate the DOM:

javascript
// select the element with the ID "my-heading"
let heading = document.getElementById("my-heading");

// change the text of the heading
heading.innerHTML = "Hello, World!";

// change the background color of the body
document.body.style.backgroundColor = "blue";

In this example, we first select the element with the ID "my-heading" using document.getElementById(). Then we change the text of the heading using the innerHTML property. Finally, we change the background color of the body using the style property.

I hope this helps! Let me know if you have any further questions.