Undefined Variable In Array In Prototype

I have the following code:

• Number One

Solution 1:

I think you're confusing the properties which pluck() works on with HTML attributes. It's anyway easier to add the pseudo class of checked as part of the initial selector, like:

$$('li.litemd input:checked').each(function(s) {
      alert(s.next().innerHTML);
  });

Example

Solution 2:

$$('li.litemd').pluck('checked').each(function() {
  alert($$(this).next().innerHTML)
});

?

Solution 3:

.pluck() returns an array of values (whatever property name you passed in), so it's not filtering your results to the checked ones, it's literally returning a [false, false, false] array.

Instead I think you want this:

$$('li.litemd input').each(function(s) {
  if(s.checked) alert(s.next().innerHTML)
});

You can give it a try here, note the addition of input to the selector, since you're cheking on the property of the <input>inside the <li>, not on the <li> itself.