The building blocks of an interactive web page is the JavaScript event system. An event in JavaScript is something that happens with or on the webpage. A few example of events:
JavaScript has predefined names that cover numerous events that can occur, including the ones listed above. To capture an event and make something happen when that event occurs, you must specify the event, the HTML element that will be waiting for the event, and the function(s) that will be run when the event occurs.
We have used a JavaScript event in a previous lesson, where we had an alert popup when the button was clicked. This was an "onclick" JavaScript event. We will do that same example again, as well as the mouseover and mouseout events.
<html> <head> <script type="text/javascript"> <!-- function popup() { alert("Hello World") } //--> </script> </head> <body> <input type="button" value="Click Me!" onclick="popup()"><br /> <a href="#" onmouseover="" onMouseout="popup()"> Hover Me!</a> </body> </html>