The focus event fires when an element has received focus. The event does not bubble, but the related focusin event that follows does bubble.
The opposite of focus is the blur event, which fires when the element has lost focus.
The focus event is not cancelable.
Use the event name in methods like addEventListener(), or set an event handler property.
addEventListener("focus", (event) => { })
onfocus = (event) => { }A FocusEvent. Inherits from UIEvent and Event.
<form id="form">
<label>
Some text:
<input type="text" placeholder="text input" />
</label>
<label>
Password:
<input type="password" placeholder="password" />
</label>
</form>const password = document.querySelector('input[type="password"]');
password.addEventListener("focus", (event) => {
event.target.style.background = "pink";
});
password.addEventListener("blur", (event) => {
event.target.style.background = "";
});There are two ways of implementing event delegation for this event: by using the focusin event, or by setting the useCapture parameter of addEventListener() to true.
<form id="form">
<label>
Some text:
<input type="text" placeholder="text input" />
</label>
<label>
Password:
<input type="password" placeholder="password" />
</label>
</form>const form = document.getElementById("form");
form.addEventListener(
"focus",
(event) => {
event.target.style.background = "pink";
},
true,
);
form.addEventListener(
"blur",
(event) => {
event.target.style.background = "";
},
true,
);HTMLElement.focus() methodblur, focusin, focusoutWindow targets: focus event