The scrollX property in JavaScript works the same as pageXoffset property. If you want to get the pixels the document scrolled to from the upper left corner of the window, then use the scrollX property for horizontal pixels.
Example
You can try to run the following code to learn how to work with scrollX property in JavaScript.
<!DOCTYPE html>
<html>
<head>
<style>
div {
background-color: yellow;
height: 1500px;
width: 1500px;
}
</style>
</head>
<body>
<script>
function scrollFunc() {
window.scrollBy(200, 200);
alert("Horizontal: " + window.scrollX);
}
</script>
<button onclick = "scrollFunc()" style = "position:fixed;">Scroll</button>
<br><br><br>
<div>
</div>
</body>
</html>