@Indieminor frameCount is a special keyword that returns the number of frames drawn by the draw function, it can be used to create a timer, especially if you set a framerate.
for example if you say
var seconds;
function setup() {
// do setuppy things here
seconds = 0;
frameRate(30);
then you can do
function draw() {
// do all kinds of stuff
seconds = frameCount / 30. ;
to get how many seconds have passed since you started the sketch.
( or loaded he page i just made the distinction in case of a noLoop() loop() scenario. )