When thereâs not enough of these hormones, your body has trouble with these basic functions. That causes the symptoms of adrenal insufficiency -- fatigue, muscle weakness, low appetite, weight loss, and belly pain, among others. You can have either primary or secondary adrenal insufficiency.
In the DOM event model, there is a clear distinction between an event listener and a listener function: an event listener is an instance of a class that implements the EventListener interface, whereas a listener function is a method of that class named handleEvent().
An event is something that happens. In the world of JavaScript, an event is usually something that the website visitor did, such as moving their mouse over a link. That is an event. An event handler comes into play when the event occurs. The event occurs and the event handler calls a JavaScript or reaction into play.