string search

[weescotty]

found=pilotRoster[row][col].indexOf(sortBy);

How can I make the above line case insensitive?
pilotRoster[row][col] is an Array location containing text.
sortBy is the string to search for.

eg if I search for "Cha" at the moment it will reurn Charles etc.
If I search for "cha" it will find Richard.

How can I make it so "cha" will return both Charles and Richard?

Thanks

Ignore found the solution-

found=pilotRoster[row][col].toLowerCase().indexOf(sortBy.toLowerCase());