HTML：
<button class="button">注册</button>
JS：
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`);
};
CSS：
.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;
}
&::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 0.2s ease, height 0.2s ease;
}
&:hover::before {
--size: 400px;
}
}
