Question: i have a javascript file about 6000+ lines of codes created by myself. Now it has functions for different sections of my site.. Now what i want to ask is that should i use that large file or divide it in parts for respective sections and call it in respective section.

Answer: 
It depends on how much the HTTP request cost is Vs. how likely a visitor is to access one of the sections with specific JS Vs. how much bandwidth is saved for the other pages.
Lately, it appears as if the best approach is to split it up into smaller files and load only the needed ones, in parallell, using some kind of JS loader (like [Head JS](http://headjs.com) for example; click the link and scroll down to the headline "Combining scripts" to read more about the performance difference).

Another possible loader to use would be [RequireJS](http://requirejs.org/).