Javascript Basics, Stage 3, Traversing & Manipulating the DOM Error editButton not defined.

//Problem: User interaction doesn't provide desired results
//Solution: Add interactivity so the user can mangage 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-tasks
var completedTasksHolder = document.getElementById("completed-tasks"); //completed-tasks

// Add a new task
var addTask = function() {
  console.log("Add task...");
    //When the button is pressed 
    //Create a new list item with text from #new-task:
    //imput (checkbox)
    //label
    // input (test)
    //button.edit
    //button.delete
    //Each of these elements will need to be modified and appended

}

//Edit an existing task
var editTask = function() {
    console.log("Edit task...");
    //When edit button is pressed
    //if the class of the parent is .edit
    //switch from .editmode
    //label text became the input's value
    //else
    //switch to .editmode
    //input value becomes the label's 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 from the unordered list

}  

//Mark a task as complete. 
var taskCompleted = function() {
    console.log("Task complete...");
   //When the checkbox is checked
   //append the task  list item to the #completed-tasks
}

//Mark a task as incomplete
var taskIncomplete = function() {
    console.log("Task incomplete...");
    // When the checkbox is unchecked
    //append the task list item to the #incomplete-tasks
}

var bindTaskEvents = function(taskListItem, checkBoxEventHandler) {
  console.log("Bind list item events");
  //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 editbutton
  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 incompleteTaskHolder ul list items
for(var i = 0; i < incompleteTasksHolder.children.length; i++){
    console.log("Bind list item events");
 //bind events to list item's children (taskCompleted)
 bindTaskEvents(incompleteTasksHolder.children[i], taskCompleted);
}

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