i am trying to create a button which will show/hide an image on click.it works only one time after reload.how to make it continuous.can anyone point out where the mistake lies in my code .thanks!!!
Code:
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Untitled Document</title>
<style>
#imag{
	width:300px;
	height:300px;
	display:none;
}
</style>
<script>
function show(imgs,bttn){
	if(show.last && show.lst){
		show.last.style.display="none";
		
		show.lst.setAttribute('value',"show");
		}
		
else{
	
      var s=document.getElementById(imgs);
	  var t=document.getElementById(bttn);
	  s.style.display="block";
	  t.setAttribute('value',"hide");
	  	show.last=s;
		show.lst=t;}
	
}

</script>
</head>

<body>
<div><input type="button" value="show" onClick="retrun false" onMouseDown="show('imag','btn');" id="btn"></div>
<img src="image1.jpg" id="imag">
</body>
</html>