Recently worked for ‘Building Cascading DropDownList in ASP.Net Using jQuery and JSON’.
The reason to go for this approach is the problem while using Cascading DropDown in Update Panel.
However as I had thought, the soultion is not promising with Jquery & JSON as well. i.e it Things works fine till the records are less than 1000 (1k).
It dies when the count reaches to 5k & becomes worst at 10k.
Here is where the solution and the problem - Link
Hope this helps.
Thanks & Regards,
Arun Manglick || Senior Tech Lead