Multiplying million digit integers using Javascript!
Expect your browser to completely block for about 5 to 10 seconds... Much better than nothing. (But slower than Sage/Python.)
(If you run the above in CoCalc it will output about 5000, which means "5 seconds".... depending on your browser.)
Now in Sage (fraction of a second):
CPU time: 0.02 s, Wall time: 0.02 s
In Python (1-2s):
CPU time: 1.46 s, Wall time: 1.59 s