scroll two divs simultaneously site:stackoverflow.com
// https://stackoverflow.com/questions/9236314/how-do-i-synchronize-the-scroll-position-of-two-divs/9236351
var isSyncingLeftScroll = false;
var isSyncingRightScroll = false;
var leftDiv = document.getElementById('left');
var rightDiv = document.getElementById('right');
leftDiv.onscroll = function() {
if (!isSyncingLeftScroll) {
isSyncingRightScroll = true;
rightDiv.scrollTop = this.scrollTop;
}
isSyncingLeftScroll = false;
}
rightDiv.onscroll = function() {
if (!isSyncingRightScroll) {
isSyncingLeftScroll = true;
leftDiv.scrollTop = this.scrollTop;
}
isSyncingRightScroll = false;
}