Tiny text encryption library for browser. It does use SubtleCrypto and async/await so it requires a secure context and a modern browser.
<script type="module">
import tinyEnc from "https://unpkg.com/tiny-enc";
// use it as a module or just copy/paste the code
await tinyEnc.encrypt("password", "Hello, World"); // KA+e+PmeSy0osLFTjTgrxFZAoLJ7iixh89G7TkuyHEQ=
await tinyEnc.decrypt("password", "KA+e+PmeSy0osLFTjTgrxFZAoLJ7iixh89G7TkuyHEQ="); // Hello, World
</script>