Scroll to bottom when new content is added to div

Question

How can I get the chat to scroll to bottom when new content is sent into the chat? I'm trying to add something like this:

$('#what do I have to put here?').animate({scrollTop: $('#and here?').prop("scrollHeight")}, 200);

but I can't make it work (I have no idea where in the code to place it).

Thanks!

This is an important part of the code... Maybe I have to add it here (but I don't know how or where):

<script type="text/javascript">
        var _answerBot = new answerBot();
        function keypressInput(sender, event) {
            if (event.which == 13) {
                document.getElementById('subcontent').innerHTML += _answerBot.processInput(sender.value);
                sender.value = '';


            }
        }


    </script>  

This is a separate scripts.js file:

var answerBot = function () {
    var _this = this;
    _this.processInput = function (text) {
        updateUrl(text);
        var _result = "<p class='answerbot-input'>" + text + "</p>";
        text = text.replace(new RegExp("[ ]{2,}", "g"), " ");
        var _words = text.toLowerCase().split(" ");
        var _answers = [];
        var _title = "";
        if (_words.length === 0 || _words.toString() === '') { //if the input is empty
            _answers = _this.specialContext.emptyInput;
            _title = _this.specialContext.emptyInput;
        } else {
            var _possibleAnswers = findMatches(_words);
            if (_possibleAnswers.length === 0) { //if no answer found
                _answers = _this.specialContext.wrongInput;
                _title = _this.specialContext.wrongInput;
            }
            if (_possibleAnswers.length == 1) { //context recognized
                _answers = _this.answers[_possibleAnswers[0]].values;
                _title = _this.answers[_possibleAnswers[0]].description;
            }
            if (_possibleAnswers.length > 1) {
                _result += formatText(_this.specialContext.rephrase, _this.specialContext.rephrase);
                for (var i = 0; i < _possibleAnswers.length; i++) {
                    _result += formatText(_this.answers[_possibleAnswers[i]].description, _this.answers[_possibleAnswers[i]].description);
                }
            }
        }
        if (_answers.length > 0) {
            var _rand = Math.floor((Math.random() - 0.001) * _answers.length);
            _result += formatText(_answers[_rand], _title);
        }
        return _result;
    };

    function formatText(text, title) {
        return "<p class=\'answerbot-ai\' title=\'" + title + "\'>" + text + "</p>";
    }

    function findMatches(words) {
        var foundKeywords = [];
        var _possibleAnswers = [];
        for (var i = 0; i < _this.keywords.length; i++) {
            foundKeywords[i] = 0;
            for (var j = 0; j < words.length; j++) {
                if (_this.keywords[i].keys.indexOf(words[j]) >= 0) {
                    foundKeywords[i]++;
                    if (foundKeywords[i] == _this.keywords[i].keys.length) {
                        return [_this.keywords[i].value];
                    }
                }
            }
            if (foundKeywords[i] * 2 > _this.keywords[i].keys.length) {
                _possibleAnswers.push(_this.keywords[i].value);

            }
        }
        return _possibleAnswers.filter(function (elem, pos) {
            return _possibleAnswers.indexOf(elem) == pos;
        });
    }

    function updateUrl(text){
        history.pushState(null, null, "#question=" + encodeURIComponent(text));
        if(typeof ga === "function")//google analytics
            ga('send', 'event', 'question', text);
    }
};

Answer 1

 function AddMessage() { var $message = $("<p>").text("message"); var $messages = $("#messages"); $messages.append($message); $messages.animate({ scrollTop: $messages.prop("scrollHeight") }); } 

 #messages { border: 1px solid #000; height: 100px; overflow: auto; } 

 <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script> <div id="chat"> <div id="messages"></div> <button onClick="AddMessage()">Add Message</button> </div>