function setBackgroundImage()
{

	var theWidth;
	
	if(window.screen.width < 1440) {
		theWidth = '1280';
	}
	else if(window.screen.width < 1680 && window.screen.width >= 1440) {
		theWidth = '1440';
	}
	else {
		theWidth = '1680';
	}
	document.getElementById('body_page').style.backgroundImage = "url('images/backgrounds/background_" + theWidth + ".jpg')";
}

setBackgroundImage();