How to know whether checkbox is checked or not, jquery?

Question

Is there any better way to do this :

var IsC = $('input[type=checkbox]').attr("checked") == "checked" ? true : false;

?

Answer 1

You can use the :checked selector

var IsC = $('input[type=checkbox]').is(":checked");

Or :

var IsC = $('input[type=checkbox]:checked').length>0;

Answer 2

$("input[type=checkbox]").is(":checked")

Answer 3

var IsC = $('input[type=checkbox]').attr("checked") == "checked" ? true : false; 

is the same as just saying:

var IsC = $('input[type=checkbox]').attr("checked") == "checked";

since == will return true or false. (purely a javascript change)

---

The jQuery optimization (in terms of number of characters, at least) is:

var IsC = $('input:checkbox').is(':checked'); 
//returns true if at least one checkbox in the document is checked

You can add a scope for the comparison by telling the selector where the input should be found:

var IsC = $('#myForm input:checkbox').is(':checked');

Answer 4

One way is to use solution posted by dystroy.

Another is to use prop method instead of attr. Check examples at http://api.jquery.com/prop/

elem.checked
// true (Boolean) Will change with checkbox state

$(elem).prop("checked")
// true (Boolean) Will change with checkbox state

elem.getAttribute("checked")
// "checked" (String) Initial state of the checkbox; does not change

$(elem).attr("checked") //(1.6)
// "checked" (String) Initial state of the checkbox; does not change

$(elem).attr("checked") //(1.6.1+)
// "checked" (String) Will change with checkbox state

$(elem).attr("checked") //(pre-1.6)
// true (Boolean) Changed with checkbox state