which autocomplete get data from both local array and server?

I want to use autocomplete in a aspx form. Requriment is autocmplete should first check for data on local (common data will be loaded with page in javascript array). If not found than it should request the server database and search the data there.

There are many plugins, scripts and widgets avaialable. Please guide me which is best and easy to use in .aspx and also that works on both ends (first it should check on client and if not found then it should go to 开发者_如何学Pythonserver).

How much data are you caching in a JS array? We use Telerik controls to do AutoComplete and haven't had any problems with performance using an AJAX/WebService call to populate the list.

I'm sure you can achieve the same results with a free or homegrown solution as well. I'm just wondering if it's worth creating both a client and server side model for this.