To get HTML5 Tags working in Internet Explorer 7 (IE7) and Internet Explorer 8 (IE8), there is a simple workaround. Before the html head  close tag add

<!--[if lt IE 9]>
        <script>
        document.createElement('header');
        document.createElement('nav');
        document.createElement('section');
        document.createElement('article');
        document.createElement('aside');
        document.createElement('footer');
        document.createElement('hgroup');
        </script>
        <![endif]-->
    </head>

and in your css in the very first line(s)

header, nav, section, article, aside, footer, hgroup {
    display: block;
}

 

Than most html5 stuff shall work. Yes, things like input types still don’t work. That’s for sure, but at least the design won’t be broken, if you are using html5.