Question

یه سری صفحات هستند که وقتی اسکرول میکنی به آخرش باز محتوای جدید لود میکنه

Answer 1

There are a number of / some pages , which when being scrolled down, resume  to download new items / contents. 

Answer 2

There are some pages that when you scroll them to the(ir) end, again load new content.