intro.js
/**
      * Calculates the current Y scroll position of the body
      *
      * @api private
      * @return {Number} Y position of the body scroll
      */
Calculates the current Y scroll position of the body
@api private
@return {Number} Y position of the body scroll
Calculates the current Y scroll position of the body @api private @return { Number } Y position of the body scroll
function _getCurrentYPosition() {
        if (document.body && document.body.scrollTop) {
            return document.body.scrollTop;
        }
        if (document.documentElement && document.documentElement.scrollTop) {
            return document.documentElement.scrollTop;
        }
        if (window.pageYOffset) {
            return window.pageYOffset;
        }
        return 0;
    }
function _getCurrentYPosition ( ) { if ( document . body && document . body . scrollTop ) { return document . body . scrollTop ; } if ( document . documentElement && document . documentElement . scrollTop ) { return document . documentElement . scrollTop ; } if ( window . pageYOffset ) { return window . pageYOffset ; } return 0 ; }
Calculates the current Y scroll position of the body
 @api private
 @return {Number} Y position of the body scroll
Calculates the current Y scroll position of the body @api private @return { Number } Y position of the body scroll