html show/hide code example

Example 1: how hide in html

#elementID{
display:none;
}

Example 2: Show/Hide

<script type="text/javascript">
<!--
    function toggle_visibility(id) {
       var e = document.getElementById(id);
       if(e.style.display == 'block')
          e.style.display = 'none';
       else
          e.style.display = 'block';
    }
//-->
</script>