RE: how to access the inventory details on item master record using suitescript 1.0?
How to get the qty on hand, qty on order, qty backordered, under which bin number the item is, value and avg. cost of an item, through inventory detail sub record.
I tried to pick the values from a search but they werent accurate (not as per the inventory details). I can see the Inventory details in UI but there is no id or anything for loading it in ascript.
Can anyone please advise me what to do?
The inventory details on item records are sublists, specifically static sublists that dont support suitescript. You probably want to work more on creating a search that matches. My advice is to click the Customize View
button on the sublist to take a look at the search type, filters, and columns of the sublist view.

Thanks battk for your comment. i tried doing that but that search isnt scriptable.
And which search type is this? Fair chance it is supported or at the very least is available as a join from an item search

InventoryNumberBin is a supported search type. SuiteScript 2.0 documentation also makes is more explcit in its search.Type documentation that its actually a supported type outside of joins. You dont really need to use suitescript 2.0 to access the search, though you should probably do things in suitescript 2 anyways.
My guess is that you tried and failed to use the chrome NetSuite: Search Export extension. It doesnt support searches where you need to specify the type.