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JavaScript Interactive Web Pages with JavaScript Selecting Elements and Adding Events with JavaScript Perform: Event Handling

Chris Collier
Chris Collier
17,774 Points

Can't get onclick event attached to add button/firing correctly

Hi, here's my code:

//Problem: User interaction doesn't provide desired results
//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-tasks
var completedTasksHolder = document.getElementById("completed-tasks"); //completed-tasks
//Add a new task
var addTask = function() {
  console.log("Add task...");
  alert("Add task");
  //When the button is pressed
  //Create a new list item with teh text from #new-task:
    //Input (checkbox)
    //Input (text)
    //Each element needs modified and appended

//Edit an existing task
var editTask = function() {
  console.log("Edit task...");
    //When the Edit button is pressed
      //If the class of the parent is .editMode
        //Switch from .editMode
        //Label text become the input's value
        //Switch to .editMode
        //Input value become's 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 ul

//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

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

I believe I've copied it very well from what is in the videos. When I click the addButton, there's supposed to be a console.log "Add task...", but it isn't working. I tried adding an alert(), but no dice there either.

In the console, addButton correctly refers to the HTML:


However, addButton.onclick returns null. Does anyone know what I'm doing wrong?

4 Answers

Austin Whipple
Austin Whipple
29,725 Points

You may need to invoke the function with the parenthesis:

addButton.onclick = addTask();

Could also give using an event listener a try:

addButton.addEventListener("click", addTask());

Chris Collier
Chris Collier
17,774 Points

Thanks I tried addEventListener and when that didn't work, I knew something was systemically wrong. It turns out that, for some reason, my browser wasn't loading the most recent .js file from Workspace. I had to clear my cache to fix.

I'm having the same issue in both chrome and firefox.

The two work arounds I've found is using:

addButton.addEventListener("click", addTask);


add an ID to the button and changing getElementsByTagName to getElementById

I still want to know why it works in the video and not in my browser (new version perhaps?)

Bonnie Martin
Bonnie Martin
13,671 Points

I had the same problem. Adding parentheses worked, like: addButton.onClick = addTask();

Does anyone know why that would be necessary? What could have changed with JavaScript or Chrome since this video was made that would make that necessary? Just curious.