If you add and remove the innerHTML, all javascript, css and more will be loaded twice, and the events will fire twice (happened to me), is better hide content, using jQuery and css like this:
function printDiv(selector) {
$('body .site-container').css({display:'none'});
var content = $(selector).clone();
$('body .site-container').before(content);
window.print();
$(selector).first().remove();
$('body .site-container').css({display:''});
}
The div "site-container" contain all site, so you can call the function like:
printDiv('.someDiv');