ddSize([768, 200], [728, 90]) //Tablet
                                              .addSize([500, 0], [[320, 100], [320, 50]]) //Mobile
                                              .build();
                                      gptAdSlots[4] = googletag.defineSlot(dfp_sitePage, [320, 100], 'adpos_bottomB')
                                              .defineSizeMapping(sizeMappings['adpos_bottomB'])
                                              .setTargeting('pos',['bottomB,bottomB,btf'])
       