CSS selectors have become increasingly sophisticated since the introduction of CSS3 more than a decade ago. This tutorial discusses three recent pseudo-class selectors which target elements based on their state.
Craig Buckler
We can not only assign handlers, but also generate events from JavaScript.
Custom events can be used to create “graphical components”. For instance, a root element of our own JS-based menu may trigger events telling what happens with the menu: open (menu open), select (an item is selected) and so on. Another code may listen for the events and observe what’s happening with the menu.
We can generate not only completely new events, that we invent for our own purposes, but also built-in ones, such as click, mousedown etc. That may be helpful for automated testing.
javascript.info
Before the Fetch API most of the React JS developers used to depend on the Axios to get the data from the server. Now, with the Fetch API being supported by the most of the browsers, many developers wants to use this instead of Axios as the Fetch API is native to the browsers and there will be no need to depend on third party library.
howtoJS