Toggle Switch Loading State
A toggle that slides on, spins a small ring inside its knob while the change saves, then fills with color once it lands, and later flips back. For settings that need a server round trip.
Also known as: switch with spinner, toggle loading spinner, async toggle switch.
HTML
<button class="ldr-loading-toggle-switch" type="button" role="switch" aria-checked="true" aria-busy="true" aria-label="Sync"> <span class="ldr-loading-toggle-switch-knob" aria-hidden="true"></span> </button>
CSS
.ldr-loading-toggle-switch {
--s: var(--ldr-size, 48px);
--c: var(--ldr-color, #3b82f6);
--pad: calc(var(--s) / 12);
--knob: calc(var(--s) * 0.9 - var(--pad) * 2);
position: relative;
width: calc(var(--s) * 1.6);
height: calc(var(--s) * 0.9);
padding: 0;
border: 0;
border-radius: calc(var(--s) * 0.45);
background: color-mix(in srgb, var(--ldr-color, #3b82f6) 28%, transparent);
cursor: progress;
}
.ldr-loading-toggle-switch::before {
content: "";
position: absolute;
inset: 0;
border-radius: inherit;
background: var(--c);
opacity: 0;
animation: ldr-loading-toggle-switch-fill 3.6s cubic-bezier(0.45, 0, 0.55, 1) infinite;
}
.ldr-loading-toggle-switch-knob {
position: absolute;
left: var(--pad);
top: var(--pad);
width: var(--knob);
height: var(--knob);
border-radius: 50%;
background: #fff;
box-shadow: 0 1px 2px rgb(0 0 0 / 0.25);
animation: ldr-loading-toggle-switch-slide 3.6s cubic-bezier(0.5, 0, 0.2, 1.2) infinite;
}
.ldr-loading-toggle-switch-knob::after {
content: "";
position: absolute;
inset: 22%;
box-sizing: border-box;
border: max(1px, calc(var(--s) / 24)) solid color-mix(in srgb, var(--ldr-color, #3b82f6) 25%, transparent);
border-top-color: var(--c);
border-radius: 50%;
animation:
ldr-loading-toggle-switch-spin 0.7s linear infinite,
ldr-loading-toggle-switch-busy 3.6s ease infinite;
}
@keyframes ldr-loading-toggle-switch-slide {
0%, 8% { transform: translateX(0); }
20%, 66% { transform: translateX(calc(var(--s) * 0.7)); }
78%, 100% { transform: translateX(0); }
}
@keyframes ldr-loading-toggle-switch-busy {
0%, 14% { opacity: 0; scale: 0.4; }
20%, 44% { opacity: 1; scale: 1; }
50%, 100% { opacity: 0; scale: 0.4; }
}
@keyframes ldr-loading-toggle-switch-fill {
0%, 44% { opacity: 0; }
52%, 68% { opacity: 1; }
76%, 100% { opacity: 0; }
}
@keyframes ldr-loading-toggle-switch-spin {
to { transform: rotate(360deg); }
}
@media (prefers-reduced-motion: reduce) {
.ldr-loading-toggle-switch, .ldr-loading-toggle-switch *, .ldr-loading-toggle-switch::before, .ldr-loading-toggle-switch::after, .ldr-loading-toggle-switch *::before, .ldr-loading-toggle-switch *::after {
animation-duration: 3s;
}
}Customizing this loader
- Color: set
--ldr-coloron the element or a parent. Currently previewing#3b82f6. - Size: set
--ldr-size. Every dimension in the snippet is derived from it. Currently previewing64px. - Speed: change the duration on the
animationshorthand. Delays on the children are relative, so they keep their rhythm. - Accessibility: the root carries
role="status"and anaria-labelso screen readers announce the wait. The reduced-motion rule at the end slows the animation for users who asked for less motion.