Combining text data but ignoring blank cells?

I'm looking to combine the text data different cells in Excel. I am currently using the formula:

=J3&", "&K3&", "&L3&", "&M3

When all my cells contain text, the outcome is exactly what I want.

However, in some cases, there are cells with no data in them. At the moment, my formula just returns " , , , " if there is no data in the cells. Is there a way to rewrite the formula so it ignores cells that don't contain any data?