The user interacts with the application via pushing keyboard keys or using the mouse. A programmer should be able to tell which key on the keyboard the user has pressed, as well as if the mouse has been moved, pressed, or released. These are also known as 'events.'
Keydown, keypress, and keyup are the three types of keyboard events.
Click, mousemove, mouseover, mousedown, mouseup, and mouse out are all distinct sorts of mouse events.
When a user moves or clicks the mouse over a document, mouse events are generated. These events are generated when the mouse pointer is above the most deeply buried element in the document, but they spread throughout the document.