anchor.diff:    
     Unfortunately, we can't use that name when we declare the variable with (#). 
     The browser forces all attribute and element names to lowercase, turning what would be `#newHero`
  -  into `#newhero`. We don't want a `newhero` variable name in our template expressions. 
  -  The Angular workaround is to spell the declaration in "snake case". When Angular encounters "#new-hero",it translates
  -  that to `newHero` for template expressions ... which is exactly what we want.
  +  into `#newhero` (all lowercase). We don't want a `newhero` variable name in our template expressions. 
     
  -  ### **keyup.enter - a KeyEvent filter** 
  -  We'll add a hero name when the user clicks the "Add" button or hits the enter key. We ignore all other keys.
  -  If we bind to `(keyup)` our event handling expression hears every key event. We'd have to
  -  examine every `$event.keyCode` and respond only if the value is "Enter".
  +  The Angular workaround is to spell the declaration in "snake case". Angular translates "#new-hero" 
  +  to `newHero` for template expressions ... which is exactly what we want.
     
  -  Angular can filter the key events for us. Angular has a special syntax for keyboard events. 
  -  We can listen for just the "enter" key by binding to Angular's `keyup.enter` pseudo-event. 
  -  Then either the `keyup.enter` or the button click event
  -  can invoke the component's `addHero` method.
  +  ### **keyup.enter filter** 
  +  We'll add a hero when the user clicks the "Add" button or hits the "Enter" key. We ignore all other keys.
  +  We accept that we might lose the new hero if the user clicks elsewhere or leaves the page
  +  without having hit "Enter" or the "Add" button first. Let's hope the users don't complain.
   
     ### **newHero refers to the `<input>` element**
     We can access the `newHero` variable from any sibling or child of the `<input>` element.
  
positive.code:   
    The syntax is simple. We assign a template expression to the DOM event name, surrounded in parentheses. 
    A click Event Binding makes for a quick illustration.
    
  code-example(language="html" ).
    &lt;button (click)="onClickMe()">Click me&lt;/button>
  :markdown
    The `(click)` to the left of the equal sign identifies the button's click event as the **target of the binding**.
    The text within quotes on the right is the "**template expression**" in which we
  
negative.code: include ../../../../_includes/_util-fns
  
  :markdown
    When the user clicks a link, pushes a button, or types on the keyboard
    we want to know about it. These user actions all raise DOM events.
  