How do I check whether a checkbox is checked in jQuery?

Question

I need to check the checked property of a checkbox and perform an action based on the checked property using jQuery.

For example, if the age checkbox is

Answer 1

Since jQuery 1.6, the behavior of jQuery.attr() has changed and users are encouraged not to use it to retrieve an element's checked state. Instead, you should use jQuery.prop():

$("#txtAge").toggle(
    $("#isAgeSelected").prop("checked") // For checked attribute it returns true/false;
                                        // Return value changes with checkbox state
);

Two other possibilities are:

$("#txtAge").get(0).checked
$("#txtAge").is(":checked")