Webshims Polyfill - Placeholder Is Hidden when adding Dynamic Content

An example showing placeholder promts are hidden when adding dynamic content or even just showing an alert box.

HTML

<script src="http://afarkas.github.com/webshim/demos/js-webshim/minified/extras/modernizr-custom.js"></script>
<script src="http://afarkas.github.com/webshim/demos/js-webshim/minified/polyfiller.js"></script>
<ul class="emailList">
    <li>
        <input type="email" class="emailAddress" value="" placeholder="Email Address" maxlength="50" required/>
    </li>
</ul>
<a class="addEmail" href="javascript:void(0)">[Add]</a>

<a class="doAlert" href="javascript:void(0)">[Alert]</a>

CSS

.user-error {
    border-color: red
}

JavaScript

var emailItem = "<li><input type=\"email\" class=\"emailAddress\" placeholder=\"Email Address\" maxlength=\"50\" required/></li>";

jQuery('.addEmail').click(function () {
    jQuery('.emailList').appendPolyfill(emailItem);
    return false;
});

jQuery('.doAlert').click(function () {
    alert('Hello!');
});