What am I doing wrong?

var backgrounds = new Array("images/tiles/pattern_044.gif","images/tiles/pattern_045.gif","images/tiles/pattern_046.gif");

// setEvents is triggered by onload in the body tag
function setEvents() {   

function changeBkg() {
  if (document.body) {
    alert(backgrounds[0]);  //this gives me images/tiles/pattern_044.gif as expected
//  document.body.style.backgroundImage="\"url("+'+backgrounds[0]+'+")\"";     // this didn't work
//	document.body.style.backgroundImage="url('backgrounds[0]')";               // this didn't work
 	document.body.style.backgroundImage="url('images/tiles/pattern_044.gif')"; // this works but I want to use the array
all I want to do is set backgroungImage using an item from the array