Question

What is an event handler?

Short answer

Answer: The purpose of an event handler is to enable interactivity in a program or application by responding to specific events, such as user actions or system triggers. Event handlers allow programmers to define custom behavior or actions in response to these events, making the application more interactive and user-friendly.

Step-by-step solution

Understand Events in Programming

In programming, an event is an action or occurrence that happens during the execution of a program. Examples of events include clicking a button, pressing a key on the keyboard, scrolling a page, or any user interaction with a program or application. Events can also be triggered by the system, such as the completion of a file download or a change in some system settings.

Define Event Handlers

An event handler is a function or a piece of code that responds to a specific event. When the event occurs, the event handler is executed. Programmers create event handlers to provide instructions for how the application should respond when a specific event takes place. In short, an event handler deals with the response to a specific event.

Understand the Purpose of Event Handlers

The purpose of an event handler is to enable interactivity in a program or application. Event handlers allow programs to respond to user actions, thereby making them more interactive. They enable programmers to define custom behavior or actions in response to specific events, such as displaying a message or updating the application's state.

Provide an Example of an Event Handler

Here is an example of an event handler in JavaScript, a popular programming language for web development. In this example, we have a button on a web page, and we want to display an alert when the button is clicked. ``` Click me ``` In this example, the function `showAlert()` is the event handler, and it is triggered when the button is clicked. The event handler in this case displays an alert with the message "Button clicked!" when the button is clicked by the user.