Static stars, in SVG, added to any page with `<script src="stars.js"></script>`, because, well, stars of course.

stars.js

var rdfx = rdfx || {};
rdfx.stars = function() {

	var
		c,
		svg,
		ns = "http://www.w3.org/2000/svg",
		cols = [
			"#fff", "#777", "#333", "#333", 
			"#222", "#222", "#222", "#111", 
			"#111", "#111", "#111", "#111"
		],

		random = function(s) {
			return Math.random()*s;
		},
	
		s = function(i, size) {
			svg = document.createElementNS(ns, "svg");
			svg.setAttributeNS(null, "width", size);
			svg.setAttributeNS(null, "height", size);
			svg.setAttributeNS(null, "viewBox", "0 0 2000 2000");
			svg.setAttributeNS(null, "preserveAspectRatio", "xMinYMin slice");		
			svg.setAttributeNS(null, "style", "position: absolute; top:0; left:0; width: 100%; padding: 0; margin: 0;");		
			document.body.insertBefore(svg, document.body.firstChild);
			
			while (i) {
				i--;
				c = document.createElementNS(ns, "circle");
				c.setAttributeNS(null, "fill", cols[Math.floor(random(9))]);
				c.setAttributeNS(null, "cx", random(2000));
				c.setAttributeNS(null, "cy", random(2000));
				c.setAttributeNS(null, "r", random(1.5));
				svg.appendChild(c);
			}
		}
	
	s(10000, 2000);

}

window.addEventListener("load", rdfx.stars);