jQuery.fn.scrollToViewPort = function(options) {
  var animTimeInterval = (typeof options.interval == "undefined")?"slow":animTimeInterval;
  return this.each(function(){
    var offSet = (typeof options.offset == "undefined")? $(this).offset().top : options.offset;
    if( $(this).offset().top <= $(window).scrollTop() || ( $(this).offset().top + $(this).height() ) >= ( $(window).scrollTop() + $(window).height() ) ){
      $('html,body').animate( { scrollTop: offSet  }, animTimeInterval );
    }
  });
}