Why is the variable b incremented?

Question

It’s javascript

var a = 2
var b = 3
var z = ++b
alert(b)

Answer 1

because your're first incrementing the value of b, and then setting it to z.

so, both b and z will be 4.

if you want b unchanged, do

var z = b + 1

Answer 2

Or use post incrementation instead of pre incrementation to slighlty modify the behaviour:

var b = 3;
var z = b++;
alert(b); // 4
alert(z); // 3