CODEWITHSUNDEEP
javascript
Renz Abaño
Renz Abaño

Reputation: 11

How to get the indexOf an element in an array

I want to get the indexOf the element in an element array in JavaScript.

Here's the code:

function redrawchatbox(chatbox) {
//chatbox is a html element.
chatbox.remove();
variable = variable - 280;
redraw = document.getElementsByName("chatbox");
// this is the error - gives me redraw.indexOf is not a function.
closedchatbox = redraw.indexOf(chatbox);
for (i = redraw.length; i > 0; i--) {
    x = i - 1;
    redraw[x].style.right = (parseInt(redraw[x].style.right.replace("px", "")) - 280) + "px";
}}

I want to get the index of the chat box closed so I can redraw all the chatbox in the right positions. When I use indexOf on the redraw array it throws me that error.

What can I do to fix this?

Upvotes: 0

Views: 133

Answers (3)

Ram
Ram

Reputation: 144689

That's because getElementsByName returns a HTMLCollection which is an array-like object not an array. You should convert the collection into an array then use the indexOf method.

var chatboxArr = [].slice.call(closedchatbox);
var index = chatboxArr.indexOf(chatbox);

The Array.prototype.slice method can be used to create a shallow copy of an array. In the above snippet the slice method is called with the collection as it's this value and as result it returns an array that contains items of the HTMLCollection.

Upvotes: 2

geekychick
geekychick

Reputation: 353

You get that error because getElementsByName returns a NodeList object.

Upvotes: 0

radiaph
radiaph

Reputation: 4081

Replace this:

closedchatbox = redraw.indexOf(chatbox);

with this:

closedchatbox = Array.prototype.indexOf.call(redraw, chatbox);

getElementsByName returns a NodeList, which is not an array but an "array-like object". It does not have an indexOf method itself, but the Array method can be applied to it in this way.

Upvotes: 0

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