JavaScript实现点击切换图片显示与次数统计

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>点击出现图片，再次点击循环出现</title>
</head>
<body>
<script type="text/javascript" defer="defer">
  var img=document.getElementById('img');
  var counts=0;
  function onButton() {
    counts++;
    if (counts%2== 0) {
      document.getElementById("img").style = "display:none";
    } else {
      document.getElementById("img").style = "display:block";
    }
  }
  function showClick() {
 alert(counts);
  }
</script>
<input type="button" value="请单击" onclick="onButton()" style="width: 100px; height: 20px;color: blue; background-color: chartreuse" >
<input type="button" value="显示单击次数" onclick="showClick()" style="width: 100px; height: 20px;color: blue; background-color: chartreuse" >
<div id="img" style="display:none"><img src="http://tools.jb51.net/static/api/pintu/images/4/main.jpg"></div>
</body>
</html>