fixed content in certain position after scrolling

scroll.js

$(window).scroll(function(){
  header_height = $('.inner_header-bg').height(); //header height
  content_height = $('.joinus-home').offset().top; //content height
  window_scroll = $(window).scrollTop(); //scrolling value
  header_footer_height= 554+115 //total height of header and footer
  pos = content_height - header_footer_height; 
  filter_col = $('.item_filter').parent().width();
  if ( pos > window_scroll) {
    $('.item_filter').css({
      'position': 'fixed',
      'top': header_height,
      'width': '100%',
      'max-width': filter_col
    })
  }
  else{
    $('.item_filter').css({
      'position': 'absolute',
      'top': pos
    })
  }
})
})