<script>var x=6; var y=0; while (x>0 && y<6) { x--; y= y+ x;} document.write(y)<\script>

Question

Anyone can me explain what is the logic behind this code?

Answer 1

The output will be 9.
In first loop:
x=6
x>0 // true, x is 6
y<6 // true, y is 0
so x-- makes x = 5
and y = 5+0=5 // y=y+x
so y = 5

In next loop:
x>0 // true, x is 5
y<6 // true, y is 5
so x-- makes x = 4
and y = 5+4=9 // y=y+4
so y = 9

and document.write(y) outputs 9.