html checkboxes associative array - how to access this array in javascript?

I'm trying to do this:

<input type="checkbox" name="appliances[microwave]">
<input type="checkbox" name="appliances[coffee-machine]">
<input type="checkbox" name="appliances[grill]">

and get access to this array in javascript like this

1.

var myarr = document.getElementsByName('appliances');
alert('here ' + myarr);

result: alert shows "here [object NodeList]"

2.

var myarr = document.getElementsByName('appliances');
    alert('here ' + myarr['grill']);

result: alert shows "here undefined"

How may I get access to this array?