In that case the method handleEvent is called in case of the event. Also addEventListener supports objects as event handlers. There are few events that only work with it, for instance transitionend and DOMContentLoaded (to be covered). The last way is the most flexible, but it is also the longest to write. In many cases that limitation is not pressing. Also can’t write lots of code in there.ĭOM properties are ok to use, but we can’t assign more than one handler of the particular event. HTML attributes are used sparingly, because JavaScript in the middle of an HTML tag looks a little bit odd and alien. Methods: elem.addEventListener(event, handler) to add, removeEventListener to remove.There are 3 ways to assign event handlers: Now event handlers are clearly separated, that may be easier to support. Let method = 'on' + () + (1) Įlem.addEventListener('mousedown', menu) HTML-attributeĪ handler can be set in HTML with an attribute named on.įor instance, to assign a click handler for an input, we can use onclick, like here: Let’s see them, starting from the simplest one. There are several ways to assign a handler. Handlers are a way to run JavaScript code in case of user actions. To react on events we can assign a handler – a function that runs in case of an event. We’ll get into more details of particular events in upcoming chapters.
transitionend – when a CSS-animation finishes.DOMContentLoaded – when the HTML is loaded and processed, DOM is fully built.focus – when the visitor focuses on an element, e.g.keydown and keyup – when a keyboard key is pressed and released.mousedown / mouseup – when the mouse button is pressed / released over an element.
mouseover / mouseout – when the mouse cursor comes over / leaves an element.contextmenu – when the mouse right-clicks on an element.click – when the mouse clicks on an element (touchscreen devices generate it on a tap).Here’s a list of the most useful DOM events, just to take a look at: All DOM nodes generate such signals (but events are not limited to DOM).
An event is a signal that something has happened.
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