Introduction
JavaScript: from a variable to fetch, no fluff
A course for people who already know markup and want the page to start working. Values, functions, arrays, objects, the DOM, events and requests to a server: exactly the foundation you can write real code with.
10 lessons118 min
To the first lessonCheatsheet nowTopics, each as its own lesson
01Values and variablesDemoWhere to put data and how to tell what exactly you put there.
10 min
02Strings and numbersBuild text from data without getting NaN in the output.
12 min
03Conditions and comparisonsHalf the bugs here aren't in the if but in how JS compares values.
11 min
04FunctionsA name for a piece of work. From here on, almost everything in JS is functions.
11 min
05ArraysTake a list of data and get another list or a single number out of it.
13 min
06ObjectsData from a server is objects. Taking them apart matters more than knowing ten array methods.
12 min
07Loops and iterationWhen you need a loop and when an array method is enough.
11 min
08DOM: find and changeA page is a tree of elements. JS can read it and change it.
12 min
09Events and formsA click, typing, a form submit: the points where your code starts running.
12 min
10AsynchronyA request takes a while. The code doesn't wait, so you need a way to wait for it.
14 min0/10 topics open. This is the course intro, not the whole course on one page.
In the knowledge base
Reference pages for the technologies on this topic: who maintains them, when to use them and what interviews ask.