How can I switch between two background-colors using js setinterval( )

Try this approach,

var i = 0;
function change() {
 var doc = document.getElementById("background");
 var color = ["black", "blue", "brown", "green"];
 doc.style.backgroundColor = color[i];
 i = (i + 1) % color.length;
}
setInterval(change, 1000);

<div id="background">&nbsp</div>