<html>
<head>
<meta name="viewport" content="minimum-scale=1,width=device-width">
<style>
body {
	width: 100%;
	margin: 0px;
	transition: transform 300ms ease;
	overflow-x: hidden;
}

body.section1 {
	transform: translateX(0%);
}

body.section2 {
	transform: translateX(-100%);
}

section {
	width: 100%;
	height: 100%;
	position: absolute;
}

#section1 {
	left: 0px;	
}

#section2 {
	left: 100%;
}
.mypossie {
  position:absolute;
  left: -1000px;
}
</style>

</head>
	<body class="section1">
		<section id="section1">
			<div id="assertMe1">
				<p>Section 1</p>
			</div>
			<button id="b1" onclick="var sect = document.getElementsByTagName('body')[0]; sect.classList.add('section2'); sect.classList.remove('section1');">Show section 2</button>
		</section>

		<section id="section2">
			<div id="assertMe2">
				<p>Section 2</p>
			</div>
			<button id="b2" onclick="var sect = document.getElementsByTagName('body')[0]; sect.classList.add('section1'); sect.classList.remove('section2'); ">Show section 1</button>
		</section>
    <section class='mypossie'>out in left field!</section>
	</body>
</html>
