Window pageYOffset
Example 1
Scroll the content by 100 pixels, and alert the pageXOffset and pageYOffset:
 window.scrollBy(100, 100);
 alert(window.pageXOffset + window.pageYOffset);
Try it Yourself »
More examples below.
Description
The pageYOffset property returns the pixels a 
document has scrolled from the upper left corner of the window.
The pageYOffset property is equal to the scrollY property.
The pageYOffset property is read-only.
Syntax
window.pageYOffset
or just:
pageYOffset
Return Value
| Type | Description | 
| A number | The number of pixels the document has scrolled from the upper left corner of the window. | 
More Examples
Create a sticky navigation bar:
// Get the navbar
const navbar = document.getElementById("navbar");
// Get the offset position of the navbar
const sticky = navbar.offsetTop;
// Add the sticky class to the navbar when you reach its scroll position. Remove the sticky class when you leave the scroll position.
function myFunction() {
  if (window.pageYOffset >= sticky) {
    navbar.classList.add("sticky")
  } 
  else {
    navbar.classList.remove("sticky");
  }
  }
 Try it Yourself »
Browser Support
pageYOffset is supported in all browsers:
| Chrome | Edge | Firefox | Safari | Opera | IE | 
| Yes | Yes | Yes | Yes | Yes | 9-11 | 
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