How to manage DOM elements

I have implemented Infinite scrolling(i.e Load records when the scrollbar reaches the bottom of the div). It works fine but after loading too many records on the page, the page becomes too heavy & causes slow rendering. Actually, I am using this technique as a replacement of a gridview so, how do i manage heavy DOM in this scenario?

asp dropdownlist dynamic value from javascript issue

I have a dropdownlist with 5 items. Value of last item is “other”. By choosing “other” appears popup with input. The value of this input i set to this item by javascript. So value becoms inserted text. When i submitting the form, it doesn’t work with this dynamic value, but other items of select works. Any ideas? Thanks very much!