Element.scrollLeft

The Element.scrollLeft property gets or sets the number of pixels that an element's content is scrolled from its left edge.

If the element's direction is rtl (right-to-left), then scrollLeft is 0 when the scrollbar is at its rightmost position (at the start of the scrolled content), and then increasingly negative as you scroll towards the end of the content.

// Get the number of pixels scrolled
var sLeft = element.scrollLeft;

sLeft is an integer representing the number of pixels that element has been scrolled from the left edge.

// Set the number of pixels scrolled
element.scrollLeft = 10;

scrollLeft can be specified as any integer value. However:

• If the element can't be scrolled (e.g., it has no overflow), scrollLeft is set to 0.
• If specified as a value less than 0 (greater than 0 for right-to-left elements), scrollLeft is set to 0.
• If specified as a value greater than the maximum that the content can be scrolled, scrollLeft is set to the maximum.

<div id="container">
  <div id="content">Click the button to slide right!</div>
</div>

<button id="slide" type="button">Slide right</button>

#container {
  width: 100px;
  height: 100px;
  border: 1px solid #ccc;
  overflow-x: scroll;
}

#content {
  width: 250px;
  background-color: #ccc;
}

const button = document.getElementById('slide');

button.onclick = function () {
  document.getElementById('container').scrollLeft += 20;
};

• MSDN's Measuring Element Dimension and Location
• Element.scrollTop
• Element.scrollTo()