A rainbow color generator

rainbow.js

function generateRainbowColors(count, createDiv){

	function rainbow(numOfSteps, step) {
		var r, g, b;
		var h = step / numOfSteps;
		var i = ~~(h * 6);
		var f = h * 6 - i;
		var q = 1 - f;
		switch(i % 6){
			case 0: r = 1; g = f; b = 0; break;
			case 1: r = q; g = 1; b = 0; break;
			case 2: r = 0; g = 1; b = f; break;
			case 3: r = 0; g = q; b = 1; break;
			case 4: r = f; g = 0; b = 1; break;
			case 5: r = 1; g = 0; b = q; break;
		}
		var c = "#" + ("00" + (~ ~(r * 255)).toString(16)).slice(-2) + ("00" + (~ ~(g * 255)).toString(16)).slice(-2) + ("00" + (~ ~(b * 255)).toString(16)).slice(-2);
	    return (c);
  	}

	if(!count) count = 50;
	if(!createDiv) createDiv = false;

	var ww = window.innerWidth;
	var w = Math.ceil(ww / 30);
	var x = 0;
	var y = 0;
	var colors = [];

	for (var i = 0; i < count; i++){
		var color = rainbow(count, i);
    	colors.push(color);

		if(createDiv) {
			var div = document.createElement("div");
			div.style.position = "absolute";
			div.style.left = x + "px";
			div.style.top = y + "px";
			div.style.width = w + "px";
			div.style.height = w + "px";
			div.style.backgroundColor = color;

			document.body.appendChild(div);

			x = x + w;
			if(x > ww){
				x = 0;
				y = y + w;

				div.style.left = x + "px";
				div.style.top = y + "px";
			}
		}
	}
}