/**
 * HomeGallery PREV button
 */
function hg_prevBtnClick(){
  var marginLeft = parseInt( $('#hg_home_gallery').css('margin-left') );
  
  if( marginLeft < 0 )
    $('#hg_home_gallery').animate({ "margin-left": "+=612" });
}


/**
 * HomeGallery NEXT button
 */
function hg_nextBtnClick(){
  var marginLeft = parseInt( $('#hg_home_gallery').css('margin-left') );
  var hgParent_Width = parseInt( $('#hg_home_gallery_parent').css('width') );
  var hgGallery_Width = parseInt( $('#hg_home_gallery').css('width') );

  /* make margin positive */
  marginLeft = marginLeft * -1;
  
  if( (marginLeft + hgParent_Width) < hgGallery_Width )
    $('#hg_home_gallery').animate({ "margin-left": "-=612" });
}