Array.prototype.forEach.call(document.getElementsByClassName('dsq-widget-item'), function(node) {
node.classList.add('some-class');
});
$("ul.dsq-widget-list li.dsq-widget-item").addClass("new-css-class-name");
/* get frame block */
var commentBlock = document.getElementById("recentcomments");
/* link contains in tag 'p', find it all */
var pTags = commentBlock.getElementsByTagName("p");
/* if tag have class 'dsq-widget-meta' - delete it */
for (i=0; i<pTags.length; i++)
if(pTags[i].className === "dsq-widget-meta")
pTags[i].parentNode.removeChild(pTags[i]);
var commentsPageURL = "http://penzaurist.ru/%D0%BE%D1%82%D0%B7%D1%8B%D0%B2%D1%8B/";
/* get each comment */
var comments = commentBlock.getElementsByTagName("li");
/* get first and second link in comments and change it */
for (i=0; i<comments.length; i++){
/* get links */
var avatarLink = comments[i].getElementsByTagName("a")[0];
var nameLink = comments[i].getElementsByTagName("a")[1];
/* change */
avatarLink.setAttribute("href", commentsPageURL);
nameLink.setAttribute("href", commentsPageURL);
}