JavaScript: binary conversion.

Recently I made a point of some hex conversion.

Binary Decimal turn:

let a = 45;
a.toString(2); //"101101"

let b = 123;
b.toString(2); // "1111011"

toString(radix)：

radix

Optional. It represents a predetermined base number, so that an integer between 2 and 36. If the argument is omitted, then the radix 10. Note, however, if the parameter is any value other than 10, the ECMAScript standard allows return any value.