Window.scrollX
The read-only scrollX
property of the
Window
interface returns the number of pixels that the document is
currently scrolled horizontally. This value is subpixel precise in modern browsers,
meaning that it isn't necessarily a whole number. You can get the number of pixels the
document is scrolled vertically from the scrollY
property.
Value
In practice, the returned value is a double-precision floating-point value indicating
the number of pixels the document is currently scrolled horizontally from the origin,
where a positive value means the content is scrolled to the left. If the document is
rendered on a subpixel-precise device, then the returned value is also subpixel-precise
and may contain a decimal component. If the document isn't scrolled at all left or
right, then scrollX
is 0.
Note: If you need an integer value, you can use Math.round()
to round it off.
In more technical terms, scrollX
returns the X coordinate of the left edge
of the current viewport. If there is no viewport, the returned value is
0.
Examples
This example checks the current horizontal scroll position of the document. If it's greater than 400 pixels, the window is scrolled back to the beginning.
if (window.scrollX > 400) {
window.scroll(0,0);
}
Notes
The pageXOffset
property is an alias for the scrollX
property:
window.pageXOffset == window.scrollX; // always true
For cross-browser compatibility, use window.pageXOffset
instead of
window.scrollX
. Additionally, older versions of Internet Explorer
(< 9) do not support either property and must be worked around by checking other
non-standard properties. A fully compatible example:
var x = (window.pageXOffset !== undefined)
? window.pageXOffset
: (document.documentElement || document.body.parentNode || document.body).scrollLeft;
var y = (window.pageYOffset !== undefined)
? window.pageYOffset
: (document.documentElement || document.body.parentNode || document.body).scrollTop;
Specifications
Specification |
---|
CSSOM View Module # dom-window-scrollx |
Browser compatibility
BCD tables only load in the browser