Ok so here's my code, trying to make it so that when a button is clicked with onclick="contactChange", etc, it will make a display block invisible:

```
<script type="text/javascript">
    window.onload; {
        var contactState = 0;
    }
        function contactChange() {
          if (contactState = 0) {
           var contact = document.getElementbyId("main");
           contact.style.display="none";
           contactState = 1;
          }  
          else if (contactState = 1) {
              var contact = document.getElementbyId("main");
              contact.style.display="block";
              contactState = 0;
          }
    }

</script>

```

My code does not seem to work, are there any errors, doing what I want to do?