HTML onshow Event Attribute - Playground Example

<!DOCTYPE html > 
<html> 
  <head> 
    <title>onshow event</title>  
  </head> 
  <body>  
  <div contextmenu="mymenu"> 
  <p>Right click here to see the context menu.!</p> 
  <menu type="context" id="mymenu" onshow="test()"> 
  <menuitem label="Refresh" onclick="window.location.reload();"></menuitem> 
  </menu>
  </div>
<script>
function test() {
  alert("EXAMPLE: The context menu will be shown!");
}
</script>
  </body> 
</html>