Mouse movement button with border-radius

index.html

<button class="button">
	<span>Hover me I'm awesome</span>
</button>

mouse-movement-button-with-border-radius.markdown

Mouse movement button with border-radius

A Pen by Tobias Reich on CodePen.

License.

script.babel

document.querySelector('.button').onmousemove = (e) => {

	const x = e.pageX - e.target.offsetLeft
	const y = e.pageY - e.target.offsetTop

	e.target.style.setProperty('--x', `${ x }px`)
	e.target.style.setProperty('--y', `${ y }px`)
	
}

style.scss

body {
	display: flex;
	justify-content: center;
	align-items: center;
	min-height: 100vh;
	background: white;
}

.button {
	position: relative;
	appearance: none;
	background: #f72359;
	padding: 1em 2em;
	border: none;
	color: white;
	font-size: 1.2em;
	cursor: pointer;
	outline: none;
	overflow: hidden;
	border-radius: 100px;
	
	span {
		position: relative;
		pointer-events: none;
	}
	
	&::before {
		--size: 0;

		content: '';
		position: absolute;
		left: var(--x);
		top: var(--y);
		width: var(--size);
		height: var(--size);
		background: radial-gradient(circle closest-side, #4405f7, transparent);
		transform: translate(-50%, -50%);
		transition: width .2s ease, height .2s ease;
	}
	
	&:hover::before {
		--size: 400px;
	}
}