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

I believe you could do this:

if ($('#isAgeSelected :checked').size() > 0)
{
    $("#txtAge").show(); 
} else { 
    $("#txtAge").hide();
}