When adding a task the <label> is undefined and I can't get it to show the text that I enter in the add item input

var taskInput = document.getElementById("new-task"); //#new-task
var addButton = document.getElementsByTagName("button")[0]; //first button
var incompleteTasksHolder = document.getElementById("incomplete-tasks"); //<ul #incomplete-tasks>
var completedTasksHolder = document.getElementById("completed-tasks"); //<ul #completed-tasks>

//New Task List Item
var createNewTaskElement = function (taskString) {
  var listItem = document.createElement("li");

  var checkBox = document.createElement("input");
  var label = document.createElement("label");
  var editInput = document.createElement("input");
  var editButton = document.createElement("button");
  var deleteButton = document.createElement("button");

  checkBox.type = "checkbox";
  editInput.type = "text";

  editButton.innerText = "Edit";
  editButton.className = "edit";
  deleteButton.innerText = "Delete";
  deleteButton.className = "delete";

  label.innerText = taskString;

  listItem.appendChild(checkBox);
  listItem.appendChild(label);
  listItem.appendChild(editInput);
  listItem.appendChild(editButton);
  listItem.appendChild(deleteButton);



  return listItem;
}

var addTask = function(taskInput) {
  console.log("Add Task");
  //create new list item with the text from #new-task
  var listItem = createNewTaskElement(taskInput.val);
  //append list item to incompleteTasksHolder
  incompleteTasksHolder.appendChild(listItem);
  bindTaskEvents(listItem, taskIncomplete);
}


var editTask = function() {
  console.log("Edit Task");
}


var deleteTask = function() {
  console.log("Delete Task");
  var listItem = this.parentNode;
  var ul = listItem.parentNode;
  //remove parent list item from ul
  ul.removeChild(listItem);
}


var taskCompleted = function() {
  console.log("complete Task");
  //append list item to completed tasks
  var listItem = this.parentNode;
  completedTasksHolder.appendChild(listItem);
  bindTaskEvents(listItem, taskIncomplete);
}


var taskIncomplete = function() {
  console.log("incomplete Task");
  var listItem = this.parentNode;
  incompleteTasksHolder.appendChild(listItem);
  bindTaskEvents(listItem, taskCompleted);
}

var bindTaskEvents = function(taskListItem, checkBoxEventHandler) {
  console.log("bind list items");  
  //select list item's children
  var checkBox = taskListItem.querySelector("input[type=checkbox]");
  var editButton = taskListItem.querySelector("button.edit");
  var deleteButton = taskListItem.querySelector("button.delete");

    //bind editTask to edit button
    editButton.onclick = editTask;

    //bind deleteTask to delete button
    deleteButton.onclick = deleteTask;

    //bind checkBoxEventHandler to checkbox
    checkBox.onchange = checkBoxEventHandler;
}

//Set the click handler to the addTask function
addButton.onclick = addTask;



//cycle over incompleteTasksHolder ul list items
for(var i = 0; i < incompleteTasksHolder.children.length; i ++) {
  //bind events to list items children (taskCompleted)
  bindTaskEvents(incompleteTasksHolder.children[i], taskCompleted);

}

//cycle over completeTasksHolder ul list items
for(var i = 0; i < completedTasksHolder.children.length; i ++) {
  //bind events to list items children (taskIncompleted)
  bindTaskEvents(completedTasksHolder.children[i], taskIncomplete);

}