jQuery script that will activate for scrolling up or down.

scroll-up-or-down.js

var iScrollPos = 0;
$(window).scroll(function () {
var iCurScrollPos = $(this).scrollTop();
  if(iCurScrollPos<=300){
      //Do nothing within 300px and down range
  }
  else {
    var spacerheight = $('header').height();
    if (iCurScrollPos > iScrollPos) {
       //Scrolling Down
    } else {
       //Scrolling Up
  }
iScrollPos = iCurScrollPos;
});