Log-In/ Account-Switch Widget

I've been searching for this code for a long time. I know people have it, and everything I do to recreate it... failed. Basically it's a widget that has two sections to fill in info. The first being a username, and the second the password. This allows people to switch from one account to the other.

Can someone please help?

Code:

    <script type="text/javascript">
        function switch_accounts() {
        jQuery.get(document.getElementById('logout').href, function() {
        jQuery.post('/login', 'login=1&username='+document.getElementById('switch_uname').value+'&password='+document.getElementById('switch_pass').value, function () {
        window.location.reload();
        });
        });
        }
        </script>
        Switch user:<hr />
        <input id="switch_uname" type="text" /><br />
        <input id="switch_pass" type="password" /><br />
        <input type="button" value="Switch user" onclick="switch_accounts();" />