Events
An event in computer science is an action or occurrence that is detected by a computer. For example, when someone clicks the button on their mouse, it generates a “mouse click event” for the computer. In real life, there are also events that might be associated with an action, like cause and effect. Here are some examples:
| Event | Action |
|---|---|
| It starts raining | People open umbrellas |
| The bell rings | Students go to class |
| The power button is pressed | The computer turns on |
| The mouse button is clicked | An application opens |
Can you think of some other events and what they might cause to happen?
In programming, an event handler is a part of your program that runs when a specific event happens (it “handles” the event). In MakeCode, an event handler block looks like a square with a gap in the middle and usually starts with the word “on”:
player.onTravelled(TravelMethod.Walk, function () {
})
blocks.onBlockPlaced(GRASS, function () {
})
mobs.onMobKilled(CHICKEN, function () {
})
player.onChat("jump", function () {
})