Лунтик,
<!DOCTYPE html>
<html>
<meta charset="utf-8">
<body>
<p><input maxlength="200" size="5" id="user" ></p>
<p><input maxlength="200" size="5" id="user" ></p>
<p><input maxlength="200" size="5" id="user" ></p>
<p><input maxlength="200" size="5" id="user" ></p>
<p><input maxlength="200" size="5" id="user" ></p>
<p><input maxlength="200" size="5" id="user" ></p>
<p><input maxlength="200" size="5" id="user" ></p>
<script>
const inps = document.querySelectorAll('[id="user"]');
inps.forEach((input, i) => {
const next = inps[++i % inps.length];
input.addEventListener('keydown', event => {
if(event.code == 'Enter' || event.code == 'Tab') (event.preventDefault(), next.select(), next.focus())
});
})
</script>
</body>
</html>
