<!DOCTYPE html>
<html>
<head>
</head>
<body>
Enter password: <input type="text" id="input-text-id" onblur="toLowerCase()">
<script>
function toLowerCase()
{
var txt = document.getElementById("input-text-id");
txt.value = txt.value.toLowerCase();
}
/*
run:
When you leave the input text field toLowerCase() triggered
*/
</script>
</body>
</html>