oscillation.js

var square = document.getElementById("square");

var red = 255;
var green = 0;
var blue = 0;
var towardsBlue = true;

setInterval(function(){

	// template literal:
	square.style.backgroundColor = `rgb(${red}, ${green}, ${blue})`;

	if(towardsBlue == true){
		blue = blue + 40;
		red = red - 40;
	}else{
		blue = blue - 40;
		red = red + 40;
	}
	
	// if we reach the maximums, switch direction
	if(blue >= 255 && red <= 0){
		towardsBlue = false;
	}else if(red >= 255 && blue <= 0){
		towardsBlue = true;
	}


}, 500)