autoscroll.js

{
    let scrollDiv = document.getElementById('messageViewContainer').children[0];
    let lastHeight = 0;
    window.ss = false;
    function csr() {
        if (window.ss) {
            window.ss = false;
            return;
        }
        let newHeight = scrollDiv.scrollHeight;
        if (newHeight !== lastHeight) {
            scrollDiv.scrollTop = 0;
            lastHeight = newHeight;
            setTimeout(csr, 150);
        } else {
            console.error('stopped auto scroll');
        }
    }
    csr();
}