<!DOCTYPE html><html><head><meta charset="utf-8"></head><body>
<!-- Simplest form with username and password fields. -->
<input id="form-basic-username" name="username">
<input id="form-basic-password" name="password" type="password">
<input id="form-basic-submit" type="submit">
<button id="add">Add input[type=password]</button>
<script>
document.getElementById("add").addEventListener("click", function () {
var node = document.createElement("input");
node.setAttribute("type", "password");
document.querySelector("body").appendChild(node);
});
</script>
</body></html>