<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<p><span id="btn">Password</span> <span id="txt">******</span><br></p>
<script>
btn.onclick=function(){
txt.innerHTML=["******","12345678"][+/\*+/.test(txt.innerHTML)]
}
</script>
</body>
</html>