$("input").click(function(){ var $count = $("input:checked").length; var $not = $('input').not(':checked'); if($count >= 3) { $not.attr("disabled",true); }else{ $not.attr("disabled",false); } });
<input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1"><br /> <input type="checkbox" value="1">