Just like HTML DOM events, React can perform actions based on user events.
React has the same events as HTML: click, change, mouseover etc.
Adding Events
React events are written in camelCase syntax:
onClick instead of onclick .
React event handlers are written inside curly braces:
onClick={shoot} instead of onclick="shoot()" .
React
<button onClick={shoot}>Take the Shot!</button>HTML
<button onclick="shoot()">Take the Shot!</button>Example
Put the shoot function inside the Football component:
function Football() {
const shoot = () => {
alert("Great Shot!");
}
return ( <button onClick={shoot}>Take the shot!</button> );
}
createRoot(document.getElementById('root')).render( <Football /> );Passing Arguments
To pass an argument to an event handler, use an arrow function.
Example
Send "Goal!" as a parameter to the shoot function, using arrow function:
function Football() {
const shoot = (a) => {
alert(a);
}
return ( <button onClick={() => shoot("Goal!")}>Take the shot!</button> );
}
createRoot(document.getElementById('root')).render( <Football /> );React Event Object
Event handlers have access to the React event that triggered the function.
In our example the event is the "click" event.
Example
Arrow Function: Sending the event object manually:
function Football() {
const shoot = (a, b) => {
alert(b.type);
/* 'b' represents the React event that triggered the function, in this case the 'click' event
*/
}
return ( <button onClick={(event) => shoot("Goal!", event)}>Take the shot!</button> );
}
createRoot(document.getElementById('root')).render( <Football /> );This will come in handy when we look at Form in a later chapter.