Web-Development-Applications Exam Questions & Answers

The onpopstate event is triggered in the window object when the active history entry changes, such as when the user navigates to a different page using the back or forward buttons in the browser.

History API and onpopstate:

Event: window.onpopstate

Description: This event is fired when the user navigates to a session history entry, i.e., when moving backwards or forwards in the browser history.

Example:

window.onpopstate = function(event) {

console.log('location: ' + document.location + ', state: ' + JSON.stringify(event.state));

};

Other Options:

A . Window, location: location is an object containing information about the current URL.

C . Window, name: name is a property to set or get the name of a window.

D . Window, open: open is a method to open a new browser window or tab.

MDN Web Docs - window.onpopstate

W3Schools - JavaScript History API

To ensure that there is one pixel of space between the image and the surrounding elements, the margin property should be used.

CSS Margin Property: The margin property is used to create space around elements, outside of any defined borders.

Usage Example:

img {

margin: 1px;

}

In this example, the margin: 1px; rule sets a margin of 1 pixel around the image, creating the desired space.

MDN Web Docs on Margin

W3C CSS Specification on Margin

AJAX (Asynchronous JavaScript and XML) is used to request and update data in the background without reloading the web page.

AJAX Overview:

Purpose: Allows web pages to be updated asynchronously by exchanging data with a web server behind the scenes.

Benefits: Provides a smoother user experience by avoiding full page reloads.

Example:

Using XMLHttpRequest:

var xhr = new XMLHttpRequest();

xhr.open('GET', 'data.json', true);

xhr.onreadystatechange = function() {

if (xhr.readyState === 4 && xhr.status === 200) {

var data = JSON.parse(xhr.responseText);

console.log(data);

}

};

xhr.send();

MDN Web Docs - AJAX

W3Schools - AJAX Introduction

> ''The `<datalist>` element contains a list of `<option>` elements that represent suggested options for an `<input>` element. When the input has a `list` attribute pointing to a `<datalist>`, users see a dropdown of predefined suggestions.''

Example:

```html

<input list='colors'>

<datalist id='colors'>

<option value='Red'>

<option value='Blue'>

</datalist>

```

* MDN Web Docs: datalist element

* HTML Living Standard: Forms elements

---

The

WAV: Supported in all major browsers; uses PCM encoding and is uncompressed.

Ogg (Ogg Vorbis): An open-source, patent-free audio format. Supported in Firefox, Chrome, and Opera.

MP3: Widely supported but not included in this question.

M4A and MPEG-4 Audio may or may not play consistently depending on the container and encoding, but they're less standardized across all HTML5 implementations.

WMA (Windows Media Audio): Not supported by HTML5 natively and requires proprietary plugins.

''The audio element supports formats such as MP3, WAV, and Ogg, depending on the browser. Other formats like WMA and M4A are not guaranteed to work reliably.''

HTML5 Specification (Audio section)

MDN Web Docs --

W3Schools -- HTML5 Audio Tag