Whats does this if statement mean in javaScript?

Question

if (i & Math.pow(2,j))

I didn't get what the condition is doing and how it is working? Is it equality?

http://stackoverflow.com/questions/7310109/whats-the-difference-between-and-in-javascript — str, Apr 13 '16 at 09:25
@AshiqurRahman can you add your code in the question itself? — gurvinder372, Apr 13 '16 at 09:27

score 2 · Accepted Answer · answered Apr 13 '16 at 09:41

It is building a binary code for i and it checks if a bit is set for the position of j:

var i, j;
document.write('<pre>');
for (i = 0; i < 20; i++) {
    for (j = 0; j < 20; j++) {
        document.write(i & Math.pow(2, j) ? '*' : '_');
    }
    document.write('\n');
}
document.write('</pre>');

Whats does this if statement mean in javaScript?

1 Answers1