pageX

Gets the distance in pixels between the pointer and the left edge of the page.

The page refers to the entire web page, even parts that are not currently viewable in the browser. Therefore, two clicks on the same physical point of the screen return different pageX values if the page is scrolled horizontally in the meantime. But two clicks on the same point on the page return the same pageX values even if the page is scrolled horizontally in the meantime.