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JavaScript Interactive Web Pages with JavaScript Traversing and Manipulating the DOM with JavaScript Perform: Appending and Removing Elements

Yuichi Narisawa
Yuichi Narisawa
19,548 Points

Uncaught TypeError...

I can follow the previous tutorial, but I cannot for this one. After I append listItems, console starts to complain

"Uncaught TypeError: Cannot set property 'onclick' of null at bindTaskEvents (app.js:90) at app.js:106 bindTaskEvents @ app.js:90 (anonymous) @ app.js:106"

I don't understand why this happens. Please help!

here is my workspace snapshot. https://w.trhou.se/vtfjt1k0hk

1 Answer

Ashley Carpenter
Ashley Carpenter
13,393 Points

Hi Yuichi,

It looks like your problem is because it can't find the edit button. You're trying to find an edit button with a class of edit but you didn't add an edit class when you created the button.

Try and add a class or Id to your edit button when you create it. I'll add a code example below shortly.

You'll also have the same issue with the rest of the fields.


Ashley Carpenter
Ashley Carpenter
13,393 Points
var listItem = document.createElement("li");
    //input (checkbox)
    var checkBox = document.createElement("input");// checkbox
    var label = document.createElement("label");
    //input (text)
    var editInput = document.createElement("input"); // text
    var editButton = document.createElement("button");
    edit button.addClass("edit"); // <------- here
    var deleteButton = document.createElement("button");
Yuichi Narisawa
Yuichi Narisawa
19,548 Points

Thank you for taking time to answering my question!

I carefully take a look at my code again, and find the problem! It was "()".

//Set the click handler to the addTask function addButton.onclick = addTask(); <- delete "()" : don't execute addTask function here!

Now it all works fine ;)