Can't get text from the add button to add text to the to do list.

//Problem: User interaction doesn't provide user interaction desired.
//Solution: Add interactivity so the user can manage daily tasks.
var taskInput = document.getElementById("new-task"); //new-task
var addButton = document.getElementsByTagName("button")[0]; //first button
var incompleteTasksHolder = document.getElementById("incomplete-tasks"); //incomplete-task
var completeTasksHolder = document.getElementById("completed-tasks"); //completed-tasks

//Each element needs modifying



//New Task List Item
var createNewTaskElement = function(taskString){
  //Create List item
  var listItem = document.createElement("li");
    //input checkbox
  var checkBox = document.createElement("input");
    //label
  var label = document.createElement("label");
    //input (text)
  var editInput = document.createElement("input");
    //button.edit
  var editButton = document.createElement("button");
    //button.delete
  var deleteButton = document.createElement("button");

    //Each element, needs to be modifying

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

editButton.innerText = "Edit";
editButton.className = "edit";
deleteButton.innertext = "Delete";
deleteButton.className = "delete";
label.innterText = taskString;

    //Each Element needs appendeding
  listItem.appendChild(checkBox);
  listItem.appendChild(label);
  listItem.appendChild(editInput);
  listItem.appendChild(editButton);
  listItem.appendChild(deleteButton);



  return listItem;
}

//Add a new task
var addTask = function() {
  console.log("Add task...");
  //When button is pressed
  //Create new list item with the text from the new task
  var listItem = createNewTaskElement(taskInput.value);

  //append listItem to incompleteTaskHolders
  incompleteTasksHolder.appendChild(listItem);
  bindTaskEvents(listItem, taskCompleted);

}
//Edit an existing task
var editTask = function() {
  console.log("edit task...");
  //When the edit button is pressed
    //if the class of the parent has the class edit mode
      //Switch from .editMode
      //Label text become the input
     //else
      //Switch to editMode
      //Input value becomes the labels text
    //toggle .editMode on the parent
}

//Delete an existing task
var deleteTask = function () {
  console.log("Delete Task...");
  //When the delete button is pressed
    //Remove the parent list item
  var listItem = this.parentNode;
  var ul = listItem.parentNode;
  ul.removeChild(listItem);
}
//Mark a task as complete
var taskCompleted = function() {
    console.log("Task complete");
  //When the checkbox is checked
  var listItem = this.parentNode;
  completeTasksHolder.appendChild(listItem);
  bindTaskEvents(listItem, taskIncomplete);
    //append the task list item 
}
//Mark a task as incomplete
var taskIncomplete = function() {
  console.log("Task incomplete");
  //When the checkbox is unchecked append this to imcomplete tasks
   var listItem = this.parentNode;
  incompleteTasksHolder.appendChild(listItem);
  bindTaskEvents(listItem, taskCompleted);
}

var bindTaskEvents = function(taskListItem, checkBoxEventHandler) {
  console.log("Bind Events to an Item");
  //select taskListItem'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 taskCompleted to the checkbox
  checkBox.onchange = checkBoxEventHandler;

}

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

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

//cycle over completeTaskHolder ul list items
for(var i=0; i<completeTasksHolder.children.length; i++) {
  //for each list item
    //bind events to list item's children
  bindTaskEvents(completeTasksHolder.children[i], taskIncomplete);
}