Prefill simple search criteria in the search grid

Hello, 

For Documents item type, in the search grid I need the "Classification" to be prefilled to "General" . 

I applied client side method to "classification" and "search_default" properties of Documents but it doesn't work. 

"search_default" property did not exist before so I just added it, I don't know if that makes a difference.

method: 

return {classification:{filterValue:"General",isFilterFixed:false}};