Demonstration of a for loop

Please note: This page should work correctly in Internet Explorer. I can't be certain about other browsers (Sorry!) As and when possible, I will produce a version that works whichever browser you are using.

This program shows the for loop in action, one step at a time. You will see a button below the program code. Click on the button to advance the program one step. You will also see the variables shown as small boxes at the side. The values of the variables are the values directly after the highlighted instruction shown has been carried out.

var x, sum = 0, a = 100;
for (x = 20.5; x < 99; a /= 2)
{ sum += x;	x =
x += a/2;	sum =
}	a =
alert("Sum is " + sum);