what did i do wrong

[u/Own_Stomach3061]

[u/LewdPotator]

If I'm not wrong you can't change all the tags directly, so either use index or loop the tag names.

U[0].style.display = "block";

or

for (let i = 0; i < U.length; i++) {

U[i].style.display = "block";

}

[u/Own_Stomach3061 → u/LewdPotator]

thank youuuuu

[u/HollyShitBrah → u/LewdPotator]

Or

const [U,] = document.get.....;

[u/cronixi4]

getElementsByTagName() returns a array, you can’t use .style.display on a array.

U.forEach(ul => {ul.style.display = “block”})

[u/MissinqLink → u/cronixi4]

It returns an HTMLCollection which doesn’t have array methods. If you spread to an array it will work.

[...U].forEach(x=>{x.style.display = 'block';});

I recommend using querySelectorAll because it is typically faster and returns a NodeList which does have forEach

document.querySelectorAll('ul').forEach(x=>{x.style.display = 'block';});

[u/cronixi4 → u/MissinqLink]

Ah you are right! Thought it would be the same as QuerySelectorAll().

Thanks for pointing this out!

[u/MissinqLink → u/cronixi4]

Common misconception. I’ve had to look this up more times than I can count.

[u/Medical-Swim3101]

elements by tagname will not give you a single element, you can use index or just use element.getElementByTagname

[u/Mysterious_Novel1890]

You need to go through the array that is made up of elementsbytag, and apply the style to each element