JavaScript FormData
1. Overview This chapter is about sending HTML forms: with or without files, with additional fields and so on. FormData objects can help with that. As […]
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JavaScript Fetch
1. Overview JavaScript can send network requests to the server and load new information whenever it’s needed. For example, we can use a network request […]
JavaScript File and FileReader
1. Overview A File object inherits from Blob and is extended with filesystem-related capabilities. There are two ways to obtain it. First, there’s a constructor, similar to Blob: fileParts – is […]
JavaScript Blob
1. Overview ArrayBuffer and views are a part of ECMA standard, a part of JavaScript. In the browser, there are additional higher-level objects, described in File API, […]
JavaScript TextDecoder and TextEncoder
1. Overview What if the binary data is actually a string? For instance, we received a file with textual data. The build-in TextDecoder object allows to read […]
JavaScript ArrayBuffer, binary arrays
1. Overview In web-development we meet binary data mostly while dealing with files (create, upload, download). Another typical use case is image processing. That’s all […]
JavaScript The clickjacking attack
The “clickjacking” attack allows an evil page to click on a “victim site” on behalf of the visitor. Many sites were hacked this way, including Twitter, […]
JavaScript Cross-window communication
The “Same Origin” (same site) policy limits access of windows and frames to each other. The idea is that if a user has two pages […]
JavaScript Popups and window methods
1. Overview A popup window is one of the oldest methods to show additional document to user. Basically, you just run: …And it will open […]
JavaScript Event loop: microtasks and macrotasks
Browser JavaScript execution flow, as well as in Node.js, is based on an event loop. Understanding how event loop works is important for optimizations, and sometimes […]
JavaScript Selection and Range
In this chapter we’ll cover selection in the document, as well as selection in form fields, such as <input>. JavaScript can access an existing selection, select/deselect […]
JavaScript Mutation observer
MutationObserver is a built-in object that observes a DOM element and fires a callback when it detects a change. We’ll first take a look at the […]
JavaScript Resource loading: onload and onerror
The browser allows us to track the loading of external resources – scripts, iframes, pictures and so on. There are two events for it: onload – […]
JavaScript Scripts: async, defer
1. Overview In modern websites, scripts are often “heavier” than HTML: their download size is larger, and processing time is also longer. When the browser […]
JavaScript Page: DOMContentLoaded, load, beforeunload, unload
The lifecycle of an HTML page has three important events: DOMContentLoaded – the browser fully loaded HTML, and the DOM tree is built, but external resources […]
JavaScript Forms: event and method submit
The submit event triggers when the form is submitted, it is usually used to validate the form before sending it to the server or to abort the […]
JavaScript Events: change, input, cut, copy, paste
Let’s cover various events that accompany data updates. 1. Event: change The change event triggers when the element has finished changing. For text inputs that means that […]
JavaScript Focusing: focus/blur
1. Overview An element receives the focus when the user either clicks on it or uses the Tab key on the keyboard. There’s also an autofocus HTML attribute that […]
JavaScript Form properties and methods
Forms and control elements, such as <input> have a lot of special properties and events. Working with forms will be much more convenient when we learn them. […]
JavaScript Scrolling
1. Overview The scroll event allows reacting to a page or element scrolling. There are quite a few good things we can do here. For instance: Show/hide […]
