What can JavaScript Do?

Event handlers can be used to handle, and verify, user input, user actions, and browser actions:

• Things that should be done every time a page loads
• Things that should be done when the page is closed
• Action that should be performed when a user clicks a button
• Content that should be verified when a user inputs data
• And more..

Many different methods can be used to let JavaScript work with events:

• HTML event attributes can execute JavaScript code directly.
• HTML event attributes can call JavaScript functions.
• You can assign your own event handler functions to HTML elements.
• You can prevent evetns from being sent or being handled.
• and More.

You will learn a lot more about events and event handlers in the HTML DOM chapters.