The so-called event means that JavaScript captures the user's operation and makes the correct response. For example, the user clicks the mouse to pop up a window, and moves the mouse to an element to cause changes.

JavaScript events are generally bound to DOM elements.

The basic mechanism of JavaScript event processing:

1. Bind event processing functions to DOM elements;

2. Monitor user operations;

3 .When the user performs an operation corresponding to the bound event on the corresponding DOM element, the event processing function responds;

4. Update the processing results to the HTML document.