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Michaela Zajacova
4,165 PointsCan't add new <li> items on click - getting error
Hello everyone, I have checked my code and other questions in this section but still cant figure out why I cant add a new item to the list when I click on the button I keep getting "Uncaught TypeError: Cannot read property 'appendChild' of undefined at HTMLButtonElement.<anonymous>"
Below is my code - all other functions work: JS let myHeading = document.querySelector("h1");
const toggleList = document.getElementById("toggleList"); const listDiv = document.querySelector(".list");
const descriptionInput = document.querySelector("input.description"); const descriptionP = document.querySelector("p.description"); const descriptionButton = document.querySelector("button.description");
const addItemInput = document.querySelector(".addItemInput"); const addItemButton = document.querySelector(".addItemButton");
toggleList.addEventListener("click", () => {
if (listDiv.style.display === "none") {
toggleList.textContent = "Hide List";
listDiv.style.display = "block";
} else {
toggleList.textContent = "Show List";
listDiv.style.display = "none";
}
})
descriptionButton.addEventListener("click", () => { descriptionP.innerHTML = descriptionInput.value + ':'; descriptionInput.value = " ";
});
// this does not work addItemButton.addEventListener("click", () => { let ul = document.getElementsByTagName("ul")[0]; let li = document.createElement("li"); li.textContent = addItemInput.value; ul.appendChild(li); addItemInput.value = " "; });
HTML
<!DOCTYPE html>
<html>
<head>
<title>JavaScript and the DOM</title>
<link rel="stylesheet" href="css/style.css">
</head>
<body>
<h1 id="myHeading">JavaScript and the DOM</h1>
<p>Making a web page interactive</p>
<button id="toggleList">Hide List</button>
<div class="list">
<p class="description">Things that are purple:</p>
<input type="text" class="description">
<button class="description">Change the list</button
<ul>
<li>grapes</li>
<li>amethyst</li>
<li>lavender</li>
<li>plums</li>
</ul>
<input type="text" class="addItemInput">
<button class="addItemButton">Add Item</button>
</div>
<script src="app.js"></script>
</body>
</html>
Could anyone help please?
1 Answer
Lachlan Stevens
10,779 PointsTo make it a little easier for others to help you, you can use the markdown syntax in the "Markdown Cheatsheet" to make the code a little human readable. For example, when pasting blocks of code, wrap your code with 3 backticks (```) on the line before and after. If you specify the language after the first set of backticks, that'll help us with syntax highlighting.
```html
<p>This is code!</p>
```
The specific problem you've highlighted appears to be because you haven't closed your button element here:
<button class="description">Change the list</button <ul>
Hope this helps!