function writeComment() {
	var radios = document.forma.commentUser;
	for (var i = 0, length = radios.length; i < length; i++) {
		if (radios[i].checked) {
			var comment = radios[i].value;
			document.getElementById("comments").innerHTML = comment;
			break;
		}
	}
	
}

<script src="http://DomainName/wp-includes/js/jquery/jquery.js?ver=1.11.1"></script>

<script>
jQuery(function() {
jQuery('#share-facebook').on('click', function(){
    var u = location.href;
    var t = document.title;
    sharePopup('[url]http://www.facebook.com/sharer.php?u='[/url] encodeURIComponent(u) '&t=' encodeURIComponent(t));
    return false;
});


jQuery('#share-twitter').on('click', function(){
    var u = location.href;
    var t = document.title ' - ';
    sharePopup('[url]http://twitter.com/share?url='[/url] encodeURIComponent(u) '&text=' encodeURIComponent(t) '&via=ChrisKanze');
    return false;
});

jQuery('#share-google').on('click', function(){
    var u = location.href;
    var t = document.title;
    sharePopup('[url]https://plus.google.com/share?url='[/url] encodeURIComponent(u) '&text=' encodeURIComponent(t));
    return false;
});

jQuery('#share-linkedin').on('click', function(){
    var u = location.href;
    var t = document.title;
    var d = $("meta[name='description']").attr('content');
    sharePopup('[url]http://www.linkedin.com/shareArticle?mini=true&url='[/url] encodeURIComponent(u) '&title=' encodeURIComponent(t) '&summary=' encodeURIComponent(d) '&source=' encodeURIComponent('[url]http://www.chriskanze.com[/url]') '');
    return false;
});
});
function sharePopup(url){
    var width = 600;
    var height = 400;
   
    var leftPosition, topPosition;
    leftPosition = (window.screen.width / 2) - ((width / 2)   10);
    topPosition = (window.screen.height / 2) - ((height / 2)   50);

    var windowFeatures = "status=no,height="   height   ",width="   width   ",resizable=yes,left="   leftPosition   ",top="   topPosition   ",screenX="   leftPosition   ",screenY="   topPosition   ",toolbar=no,menubar=no,scrollbars=no,location=no,directories=no";

    window.open(url,'Social Share', windowFeatures);
}
</script>