javascript - How do I force lowercase on an input field? -

i have input field client wants lowercase only. output generates input lowercase.

this have , isn't working.

<script> function tolowercase(email) {     strinput.value=strinput.value.tolowercase(); } </script>

use oninput:

var input = document.getelementsbytagname("input")[0] // input element    input.oninput = function() {    input.value = input.value.tolowercase()  }

<input type="text" />

Stadnd