What is ++a or --a ?

Answer 1

The same as a++ or a--, but the increment happens immediately, instead of after the statement.

var x = 1;
document.write(x++); // the output would be 1
// now x is 2
document.write(++x); // the output would be 3

Answer 2

As I already explain the different position determines when it happens, not what happens.

Answer 3

simply saying pre increment and post increment works similarly but.... ++a does addsn and --a does subsn by one. it first increment / decrements then executes.

Answer 4

So is la a++ or a--