// A simple function which takes a name and saves 
  // it to the current context
  function User( name ) {
      this.name = name;
  }
  
  // Create a new instance of that function, with the specified name
  var me = new User( "My Name" );
  
  // We can see that it's name has been set as a property of itself
  alert( me.name == "My Name" );
  
  // And that it is an instance of the User object
  alert( me.constructor == User );
  
  // Now, since User() is just a function, what happens
  // when we treat it as such?
  User( "Test" );
  
  // Since it's 'this' context wasn't set, it defaults to the global 'window'
  // object, meaning that window.name is equal to the name provided
  alert( window.name == "Test" );