Start with a blank first line.
alert("\nText in line 1\nnext in line 2");
Or, as is intended, use the first line for a title:
alert("Title for my List\nText in line 1\nnext in line 2");
Oh, that's a good point, the output here is platform dependent because the alert system uses OS services. So, you see this auto-titling only on Macs.
guess 1-0 for macs again, still like windows better.
Yes, it works on Mac
make 1st line bold
make no bold lines. I see, it is mac's feature)