$(document).ready(function() {

    var addItem = function() {
      $('.mainList').append('<li class="listItem"><input id="check" class="checkBox" type="checkbox"><input class="textInp" type="text" placeholder="..."></li>');
    };
    
    /*var donE = function() {
        var checkED = $("input[type='checkbox']");
        if (checkED.is(':checked')) {
            checkED.parent().remove();
        }
    };*/
    
    var Massage = function() {
        if ($(this).is(':checked')) {
            alert("Checked!");
        } else {
            alert("Unchecked!");
        }
    };
    
    $('.mainList').on('click', '#check', Massage);
    $('.addItem').click(addItem);
});
@@ -239,200 +239,19 @@
     
-/*
 var 
-donE = function() %7B%0A        var checkED = $(%22input%5Btype='checkbox'%5D%22);%0A        if (checkED.is(':checked')) %7B%0A            checkED.parent().remove();%0A        %7D%0A    %7D;*/%0A    %0A    var Massag
+itemDon
 e = 
@@ -449,14 +449,15 @@
 k', 
-Massag
+itemDon
 e);%0A

Clean up javascript