CommunityID/modules/install/views/scripts/complete/index.phtml

<h3>
    <?= $this->translate('The installation was performed successfully') ?>
</h3>
<div style="margin-top:20px">
    <div>
        <?= $this->translate('You can login as the administrator with the username and password you just provided.') ?><br />
        <?= $this->translate('Please note that this user is only meant for administrative tasks, and cannot have an OpenID credential.') ?>
    </div>
    <div style="margin-top:20px">
        <input type="button" id="start" value="<?php echo $this->translate('Finish') ?>" />
    <div>
    <script type="text/javascript">
        var oButton = new YAHOO.widget.Button(
            "start",
            {
                onclick: {fn: function() {location.href="<?php echo $this->base ?>/"}}
            }
        );
    </script> 
</div>