---
id: create-modify-element
# title: Create / modify DOM nodes
# sidebar_label: DOM Manipulation
title: DOM Manipulation
slug: /
---

import Admonition from "../components/Admonition"
import Accordion from "../components/Accordion"

## Finding elements

### 1. `querySelector()`

This method returns the **first element that matches the CSS selector**. If no match is found, it returns `null`.

```js
var ele = document.querySelector(selector);

// Ex. - body > div.container > div.box + div.box
document.querySelector(".box"); // returns first div.box
document.querySelector(".not-found"); // null
```

<Accordion>
  <Admonition type="note" title="Extra">
  This method is also available on all DOM nodes. If you want to look within a specific element, this is very useful.

  ```js
  // Example - div.outer > div.inner
  outerEle.addEventListener((ev) => {
    var innerEle = ev.target.querySelector(".inner");
  });
  ```
  </Admonition>
</Accordion>

[Read on MDN](https://developer.mozilla.org/en-US/docs/Web/API/Element/querySelector)

### 2. `querySelectorAll()`

This method returns **all the elements that match** the specified CSS selector.

It returns a **static NodeList**, which contains the matching elements. If no match is found, it returns empty NodeList.

:::note How to consume NodeList?  
 NodeList is a iterable, so it can be iterated using `for..of` loop, or converted to a array using spread syntax like `[...nodelist]`.

Here, the NodeList is static - meaning any changes in the DOM later does not affect the content of the existing collection. More about NodeList [here](https://developer.mozilla.org/en-US/docs/Web/API/NodeList).  
:::

```js
var paragraphs = document.querySelectorAll("p");

for (var p of paragraphs) {
  p.className = "note";
}
```

[Read on MDN](https://developer.mozilla.org/en-US/docs/Web/API/Element/querySelectorAll)

## Create / insert element

### 1. `createElement()`

The `document.createElement` method creates a new HTML element, taking the tag name (`"div"`) as first argument.

To set attributes and add the element to DOM, look at `.setAttribute` and `.appendChild` below.

```js
var newEle = document.createElement("div") // creates <div/>
```

<Accordion title="Related">
  <Admonition type="note" title="Creating text node">
    To add some text inside a element, you'll need to create a <b>text node</b>. 
    `createTextNode` method takes a string as input and returns a new TextNode.

  ```js
  var newEle = document.createElement("div")
  var newText = document.createTextNode("Hello world")

  newEle.appendChild(newText) // <div>Hello world</div>
  ```
  </Admonition>
</Accordion>

[Read on MDN](https://developer.mozilla.org/en-US/docs/Web/API/Document/createElement)

### 2. `setAttribute()`

Every element has a `.setAttribute(name, value)` method, which can add/modify a attribute on the current element. 

`name` - the attribute name which should be added. Ex- `"type"`.  
`value` - value of the attribute. Ex- `"text"`.

```js
var newInput = document.createElement("input")

newInput.setAttribute("type", "text") // <input type="text"/>
```

[Read on MDN](https://developer.mozilla.org/en-US/docs/Web/API/Element/setAttribute)