https://stackoverflow.com/questions/22001305

by juvian

HTML

<form action="login.php" method="post">
    <!-- Username form -->
    <div id="form1">
        <input type="text" id="username" name="username" placeholder="username"/>
            <input type="button"  value="" id="test1" />
    </div>
    <!-- Password form -->
    <div id="form2">
        <input type="password" id="password" name="password" placeholder="password"/>
            <input id="button" type="submit" value="" disabled=""/>
    </div>
    </form>

JavaScript

$("#test1").click(function(){switchForm()});
function switchForm() {
   $("#button").removeAttr('disabled');//enable
   document.getElementById("form1").style.display = "block";
   document.getElementById("form2").style.display = "block";
   document.getElementById("password").focus();
}