# Email input with live validation

> Turns green with a tick for a valid email, or red with a little shake and a hint if not.

- Category: [Inputs](https://library.aimran.es/components/inputs)
- Built with: HTML + CSS
- Live editor: https://library.aimran.es/blocks/uv-in2-valid
- Library: AIMRAN Library (https://library.aimran.es), free, no sign-up, by Aimran Oukham

## Where to use it

Catching a typo in an email address before the form is sent saves everyone a headache. Put it in the newsletter box of a site footer, the sign-up step of an app or the guest checkout of a shop. It checks when you leave the field or press Enter, not mid-typing. Email validation in HTML, CSS and JavaScript.

It only checks the format, not whether the address really exists, so keep validating on your server too. Rewrite the hint in your own words; “Looks like a letter is missing” feels kinder than a stiff error.

## Code

### HTML

```html
<label class="uv-in2v"><input placeholder="you@email.com"><span class="ic"><svg class="ok" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="3" stroke-linecap="round" stroke-linejoin="round"><path d="M5 12.5l4.5 4.5L19 7.5" pathLength="1"/></svg><svg class="no" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.8" stroke-linecap="round"><path d="M6 6l12 12M18 6L6 18"/></svg></span><em class="hp">Enter a valid email</em></label>
```

### CSS

```css
.uv-in2v {
  --c1: #0071e3;
  --c2: #8ec5ff;
  --s: 16px;
  /* tamaño */
  --k: 1;
  /* velocidad */
  --fg: #1d1d1f;
  /* texto */
  --bg: #f5f5f7;
  /* fondo */
}

.uv-in2v {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: block;
  width: 16.5em;
}

.uv-in2v input {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  width: 100%;
  box-sizing: border-box;
  padding: .9em 3em .9em 1em;
  font-size: var(--s);
  color: var(--fg);
  background: color-mix(in srgb,var(--fg) 5%,transparent);
  border: 0;
  outline: 0;
  border-radius: .85em;
  box-shadow: inset 0 0 0 1.6px color-mix(in srgb,var(--fg) 10%,transparent);
  transition: box-shadow calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v input:focus {
  box-shadow: inset 0 0 0 1.8px var(--c1);
}

.uv-in2v .ic {
  position: absolute;
  right: 1em;
  top: 1.25em;
  display: grid;
  place-items: center;
  width: 1.3em;
  height: 1.3em;
}

.uv-in2v .ic svg {
  position: absolute;
  width: 1.15em;
  height: 1.15em;
  opacity: 0;
  scale: .5;
  transition: all calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1);
}

.uv-in2v .ok {
  color: #34c759;
}

.uv-in2v .ok path {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  transition: stroke-dashoffset calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v .no {
  color: #ff375f;
}

.uv-in2v .hp {
  display: block;
  margin-top: .5em;
  padding-left: .2em;
  font-size: calc(var(--s) * .74);
  font-style: normal;
  color: #ff375f;
  opacity: 0;
  transform: translateY(-.3em);
  transition: all calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v.ok input {
  box-shadow: inset 0 0 0 1.8px #34c759;
}

.uv-in2v.ok .ok {
  opacity: 1;
  scale: 1;
}

.uv-in2v.ok .ok path {
  stroke-dashoffset: 0;
}

.uv-in2v.bad input {
  box-shadow: inset 0 0 0 1.8px #ff375f;
  animation: uv-in2v calc(0.42s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v.bad .no {
  opacity: 1;
  scale: 1;
}

.uv-in2v.bad .hp {
  opacity: 1;
  transform: none;
}

@keyframes uv-in2v {
  0%,100% {
    translate: 0;
  }
  20% {
    translate: -6px;
  }
  40% {
    translate: 5px;
  }
  60% {
    translate: -3px;
  }
  80% {
    translate: 2px;
  }
}
```

### JavaScript

```js
document.querySelectorAll(".uv-in2v").forEach(el => {
  const i=el.querySelector("input");const ck=()=>{const v=i.value.trim();el.classList.remove("ok","bad");if(!v)return;el.classList.add(/^[^@\s]+@[^@\s]+\.[a-z]{2,}$/i.test(v)?"ok":"bad")};i.addEventListener("input",()=>{if(el.classList.contains("bad"))el.classList.remove("bad")});i.addEventListener("blur",ck);i.addEventListener("keydown",e=>{if(e.key==="Enter")ck()})
});
```

### React

```tsx
// @ts-nocheck: setup() es JavaScript del DOM sin tipos, el mismo de la pestaña JS.
import { useEffect, useRef, type CSSProperties } from "react";

const css = `
.uv-in2v {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: block;
  width: 16.5em;
}

.uv-in2v input {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  width: 100%;
  box-sizing: border-box;
  padding: .9em 3em .9em 1em;
  font-size: var(--s);
  color: var(--fg);
  background: color-mix(in srgb,var(--fg) 5%,transparent);
  border: 0;
  outline: 0;
  border-radius: .85em;
  box-shadow: inset 0 0 0 1.6px color-mix(in srgb,var(--fg) 10%,transparent);
  transition: box-shadow calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v input:focus {
  box-shadow: inset 0 0 0 1.8px var(--c1);
}

.uv-in2v .ic {
  position: absolute;
  right: 1em;
  top: 1.25em;
  display: grid;
  place-items: center;
  width: 1.3em;
  height: 1.3em;
}

.uv-in2v .ic svg {
  position: absolute;
  width: 1.15em;
  height: 1.15em;
  opacity: 0;
  scale: .5;
  transition: all calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1);
}

.uv-in2v .ok {
  color: #34c759;
}

.uv-in2v .ok path {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  transition: stroke-dashoffset calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v .no {
  color: #ff375f;
}

.uv-in2v .hp {
  display: block;
  margin-top: .5em;
  padding-left: .2em;
  font-size: calc(var(--s) * .74);
  font-style: normal;
  color: #ff375f;
  opacity: 0;
  transform: translateY(-.3em);
  transition: all calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v.ok input {
  box-shadow: inset 0 0 0 1.8px #34c759;
}

.uv-in2v.ok .ok {
  opacity: 1;
  scale: 1;
}

.uv-in2v.ok .ok path {
  stroke-dashoffset: 0;
}

.uv-in2v.bad input {
  box-shadow: inset 0 0 0 1.8px #ff375f;
  animation: uv-in2v calc(0.42s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v.bad .no {
  opacity: 1;
  scale: 1;
}

.uv-in2v.bad .hp {
  opacity: 1;
  transform: none;
}

@keyframes uv-in2v {
  0%,100% {
    translate: 0;
  }
  20% {
    translate: -6px;
  }
  40% {
    translate: 5px;
  }
  60% {
    translate: -3px;
  }
  80% {
    translate: 2px;
  }
}
`;

// Interacción en JavaScript del DOM: la misma que en la pestaña JS.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function setup(el: any) {
  const i=el.querySelector("input");const ck=()=>{const v=i.value.trim();el.classList.remove("ok","bad");if(!v)return;el.classList.add(/^[^@\s]+@[^@\s]+\.[a-z]{2,}$/i.test(v)?"ok":"bad")};i.addEventListener("input",()=>{if(el.classList.contains("bad"))el.classList.remove("bad")});i.addEventListener("blur",ck);i.addEventListener("keydown",e=>{if(e.key==="Enter")ck()})
}

export default function In2Valid() {
  const ref = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const el = ref.current?.firstElementChild;
    return el ? setup(el) : undefined;
  }, []);

  return (
    <>
      <style>{css}</style>
      <div
        ref={ref} style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <label className="uv-in2v"><input placeholder="you@email.com" /><span className="ic"><svg className="ok" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="3" strokeLinecap="round" strokeLinejoin="round"><path d="M5 12.5l4.5 4.5L19 7.5" pathLength="1" /></svg><svg className="no" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.8" strokeLinecap="round"><path d="M6 6l12 12M18 6L6 18" /></svg></span><em className="hp">Enter a valid email</em></label>
      </div>
    </>
  );
}
```

## Prompt for AI assistants

Paste this into ChatGPT, Claude, Cursor, v0 or Lovable to adapt the block to your stack (Tailwind, Vue, Svelte…):

````text
I want to add the “Email input with live validation” block (Inputs) from AIMRAN Library to my project.

## What it is
Turns green with a tick for a valid email, or red with a little shake and a hint if not.

## Chosen settings
- Main color: #0071e3
- Secondary color: #8ec5ff
- Size: 16px (from 12 to 24px)
- Speed: 1x (from 0.5 to 2x)
- Text: "you@email.com"

## What I need
1. Add it to my project with the same look and animation as the reference code: same sizes, colours, radii, shadows, timings and easing.
2. It is built with plain HTML and CSS (the reference wraps it in a React component with its CSS). If my project uses something else (Vue, Svelte, Astro, plain HTML…), translate it without losing any behaviour. If I use Tailwind, turn the styles into classes; if not, keep the CSS in its own file.
3. Expose the settings above as props (or CSS variables) with those values as defaults.
4. Make it work well on phones: nothing that depends only on hover, touch targets of at least 44 px and no overflow on 320 px screens.
5. Make it look right in light and dark mode.
6. Keep it accessible: semantic HTML, roles and aria-* where needed, visible focus and keyboard support.
7. Respect prefers-reduced-motion: with reduced motion, no big animations but the same end result.

## Reference code
```tsx
// @ts-nocheck: setup() es JavaScript del DOM sin tipos, el mismo de la pestaña JS.
import { useEffect, useRef, type CSSProperties } from "react";

const css = `
.uv-in2v {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  font-size: var(--s);
  color: var(--fg);
  -webkit-tap-highlight-color: transparent;
  position: relative;
  display: block;
  width: 16.5em;
}

.uv-in2v input {
  font-family: -apple-system,BlinkMacSystemFont,"SF Pro Text","Inter",system-ui,sans-serif;
  width: 100%;
  box-sizing: border-box;
  padding: .9em 3em .9em 1em;
  font-size: var(--s);
  color: var(--fg);
  background: color-mix(in srgb,var(--fg) 5%,transparent);
  border: 0;
  outline: 0;
  border-radius: .85em;
  box-shadow: inset 0 0 0 1.6px color-mix(in srgb,var(--fg) 10%,transparent);
  transition: box-shadow calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v input:focus {
  box-shadow: inset 0 0 0 1.8px var(--c1);
}

.uv-in2v .ic {
  position: absolute;
  right: 1em;
  top: 1.25em;
  display: grid;
  place-items: center;
  width: 1.3em;
  height: 1.3em;
}

.uv-in2v .ic svg {
  position: absolute;
  width: 1.15em;
  height: 1.15em;
  opacity: 0;
  scale: .5;
  transition: all calc(0.35s / var(--k)) cubic-bezier(.34,1.56,.64,1);
}

.uv-in2v .ok {
  color: #34c759;
}

.uv-in2v .ok path {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  transition: stroke-dashoffset calc(0.35s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v .no {
  color: #ff375f;
}

.uv-in2v .hp {
  display: block;
  margin-top: .5em;
  padding-left: .2em;
  font-size: calc(var(--s) * .74);
  font-style: normal;
  color: #ff375f;
  opacity: 0;
  transform: translateY(-.3em);
  transition: all calc(0.3s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v.ok input {
  box-shadow: inset 0 0 0 1.8px #34c759;
}

.uv-in2v.ok .ok {
  opacity: 1;
  scale: 1;
}

.uv-in2v.ok .ok path {
  stroke-dashoffset: 0;
}

.uv-in2v.bad input {
  box-shadow: inset 0 0 0 1.8px #ff375f;
  animation: uv-in2v calc(0.42s / var(--k)) cubic-bezier(.25,.1,.25,1);
}

.uv-in2v.bad .no {
  opacity: 1;
  scale: 1;
}

.uv-in2v.bad .hp {
  opacity: 1;
  transform: none;
}

@keyframes uv-in2v {
  0%,100% {
    translate: 0;
  }
  20% {
    translate: -6px;
  }
  40% {
    translate: 5px;
  }
  60% {
    translate: -3px;
  }
  80% {
    translate: 2px;
  }
}
`;

// Interacción en JavaScript del DOM: la misma que en la pestaña JS.
// eslint-disable-next-line @typescript-eslint/no-explicit-any
function setup(el: any) {
  const i=el.querySelector("input");const ck=()=>{const v=i.value.trim();el.classList.remove("ok","bad");if(!v)return;el.classList.add(/^[^@\s]+@[^@\s]+\.[a-z]{2,}$/i.test(v)?"ok":"bad")};i.addEventListener("input",()=>{if(el.classList.contains("bad"))el.classList.remove("bad")});i.addEventListener("blur",ck);i.addEventListener("keydown",e=>{if(e.key==="Enter")ck()})
}

export default function In2Valid() {
  const ref = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const el = ref.current?.firstElementChild;
    return el ? setup(el) : undefined;
  }, []);

  return (
    <>
      <style>{css}</style>
      <div
        ref={ref} style={{
          "--c1": "#0071e3",
          "--c2": "#8ec5ff",
          "--s": "16px",
          "--k": "1",
          "--fg": "#1d1d1f",
          "--bg": "#f5f5f7",
        } as CSSProperties}
      >
        <label className="uv-in2v"><input placeholder="you@email.com" /><span className="ic"><svg className="ok" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="3" strokeLinecap="round" strokeLinejoin="round"><path d="M5 12.5l4.5 4.5L19 7.5" pathLength="1" /></svg><svg className="no" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2.8" strokeLinecap="round"><path d="M6 6l12 12M18 6L6 18" /></svg></span><em className="hp">Enter a valid email</em></label>
      </div>
    </>
  );
}
```

Give me the complete final code, ready to paste, and tell me in one line where to put it in my project.
````