The following video has a brief segment of a browser based interface that works and behaves like a worksheet. Users have access to all the navigational keystrokes you might expect in a spreadsheet, the ability to enter data in cells, plus forms for automatically filling selected ranges of cells. The "worksheet" example begins about 4 minutes into the video if you want to skip to that part. This is a case where a spreadsheet is not only more familiar with users, it's also a better data entry method. 5250 is good for a lot of things, but in this case it would lead to you getting stuck in a rut.