$(document).ready(function(){	
		$(".checkpoint_1").click(function(){
			$(".screen").css({"background":"url(/withonemotors/pjtCom/images/sub/cal_bg1.jpg);","background-size":"contain;"});
		});
		$(".checkpoint_2").click(function(){
			$(".screen").css({"background":"url(/withonemotors/pjtCom/images/sub/cal_bg2.jpg);","background-size":"contain;"});
		});
		$(".checkpoint_3").click(function(){
			$(".screen").css({"background":"url(/withonemotors/pjtCom/images/sub/cal_bg3.jpg);","background-size":"contain;"});
		});
	});