function randint(min, max) { return Math.random(); } NUM_PICS = 14; if (typeof(Storage) !== "undefined") { if (localStorage.bgs) { console.log("Welcome back!"); var bgs = JSON.parse(localStorage.bgs); } else { console.log("First time here?"); var bgs = []; for (var k = 0; k < NUM_PICS; k++) { bgs.push(k); } } var j = bgs[Math.floor(Math.random() * bgs.length)]; bgs.splice(bgs.indexOf(j), 1); localStorage.bgs = JSON.stringify(bgs); if (bgs.length == 0) { localStorage.removeItem("bgs"); } console.log("Pics left: " + bgs); } else { console.log("No localStorage support!"); var j = Math.floor(Math.random() * NUM_PICS); } $("#bg").css({"background-image": `linear-gradient(rgba(0,0,0,0.56), rgba(0,0,0,0.56)), url('imgs/bg${j}.jpg')`});