Add below javascript file before closing head
<script> function toggle_password(target){ var d = document; var tag = d.getElementById(target); var tag2 = d.getElementById("showhide"); if (tag2.innerHTML == 'Show'){ tag.setAttribute('type', 'text'); tag2.innerHTML = 'Hide'; } else { tag.setAttribute('type', 'password'); tag2.innerHTML = 'Show'; } } </script>
Html:
Password : <input type="password" name="usr_pwd" id="pwd0" required/> <a href="#" onclick="toggle_password('pwd0');" id="showhide">Show</a>