Alternative ways of checking if a checkbox is checked or not.

<input id = "checkbox1" type = "checkbox" name = "one" value = "1" checked = "checked">
<input id = "checkbox2" type = "checkbox" name = "two" value = "2">
<input id = "checkbox3" type = "checkbox" name = "threr" value = "3">

$('#checkbox1').is(':checked');

$('#checkbox3').is(':checked');

$('#checkbox1:checked').length;
('#checkbox2:checked').length;

$('#checkbox1').get(0).checked;  
$('#checkbox1')[0].checked;