How would I write this function:

If A2/A1=0 or #DIV/0 Error, then enter 0.00%, otherwise enter finish
calculation.

For Example A2=2 and A1=1, in cell B2 50.00% would show up.
But if A2=0 and A1=0 (only because data hasnt been entered there yet), then
just enter 0.00%

thanx