AutoAvatars in KG Chat

var userMessages = document.getElementsByClassName("username");
var lastConverted = 0;

setInterval(function () {
    if ((len=userMessages.length) != lastConverted+1)
    {
        for (var i=lastConverted; i<userMessages.length; i++)
        {
            var uid = userMessages[i].childNodes[1].attributes['data-user'].value;
            userMessages[i].childNodes[1].style="padding-left: 20px; background: url(http://i.klavogonki.ru/avatars/" + uid +".png?updated=) no-repeat no-repeat";
            userMessages[i].replaceChild(document.createTextNode(''), users[i].childNodes[0]);
            userMessages[i].replaceChild(document.createTextNode(':'), users[i].childNodes[2]);
        }

        lastConverted = len-1;
    }
}, 500);