scroll-to-target.js

// e.g. scrollToTarget(document.getElementById('foo'));

  function getOffset(target){
    var offset = {};
    
    function getOrdinate(offsetType){
      var ord = 0;
      while (target && target !== document.body){
        if (target[offsetType]){
          ord += target[offsetType];
        }
        target = target.offsetParent;
      }
      return ord;
    }
    
    
    offset.top = getOrdinate('offsetTop');
    offset.left = getOrdinate('offsetLeft');
    
    return offset;
  }
function scrollToTarget(target){
	var pos = offset(target);
	window.scrollTo(pos.left, pos.top);
	return pos;
}

scroll-to-y.js

// e.g. scrollToY(document.getElementById('foo'));

function offsetY(target){
	var top = 0;

	while (target && target !== document.body){
		if (target.offsetTop){
			top += target.offsetTop;
		}
		target = target.offsetParent;
	}
	return top;
}

function scrollToY(target){
	var top = offsetY(target);
	window.scrollTo(window.scrollX, top);
	return top;
}