p(stopPosition = 20) { var osTop = document.documentElement.scrollTop || document.body.scrollTop if (osTop <= stopPosition) { return } goTopTimer = setInterval(function() { let osTop = document.documentElement.scrollTop || document.body.scrollTop let ispeed = Math.floor(-osTop / 5) document.documentElement.scrollTop = osTop + ispeed document.body.scrollTop = osTop + ispeed if (osTop <= stopPosition) { clearInterval(goTopTimer); } }, 16); }