
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<div id="click">click</div>
<script type="text/javascript">
window.onload = function() {
var c = document.getElementById("click");
var a = 1;
c.onclick = function() {
if (a==0) {
a = 1;
alert(a);
}
else {
a = 0;
alert(a);
}
}
}
</script>
</body>
</html>



