How do I set textarea scroll bar to bottom as a default?

I have a textarea that is being dynamically reloaded as user input is being sent in. It refreshes itself every couple seconds. When the amount of text in this textarea exceeds the size of the textarea, a scroll bar appears. However the scroll bar isn't really usable because if you start scrolling down, a couple seconds later the textarea refreshes and brings the scroll bar right back up to the top. I want to set the scroll bar to by default show the bottom most text. Anyone have an idea of how to do so?

pretty simple, in vanilla javascript:

var textarea = document.getElementById('textarea_id');
textarea.scrollTop = textarea.scrollHeight;

You can use this with jQuery

$(document).ready(function(){
    var $textarea = $('#textarea_id');
    $textarea.scrollTop($textarea[0].scrollHeight);
});

In your HTML ...

<textarea id="logTextArea" style="width:600px;height:200px;"></textarea>

In your Javascript ...

<script language="javascript">

    function loadLog(logValue) {
        logTa = document.getElementById("logTextArea")
        logTa.value = logValue;
        scrollLogToBottom()
    }

    function scrollLogToBottom() {
        logTa = document.getElementById("logTextArea")
        logTa.scrollTop = logTa.scrollHeight;
    }

    loadLog("This is my really long text block from a file ... ")

</script>

I have found that you need to put the code to set the scrollHeight into a separate function after loading the new value into the text area.

I had the same problem and found out that there is no attribute that can be set initially to get the right scrolling behaviour. However, once the text is updated in the textArea, immediately after in the same function you can set the focus() to textArea to make it scroll to bottom. You can then call focus() on some other input field as well to allow user to input in that field. This works like charm:

function myFunc() {
    var txtArea = document.getElementById("myTextarea");
    txtArea.value += "whatever"; // doesn't matter how it is updated
    txtArea.focus();
    var someOtherElem = document.getElementById("smallInputBox");
    someOtherElem.focus();
}