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Anjal Binayak Adhikari
Anjal Binayak Adhikari

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Javascript 1o1 - Working with DOM - 2

This article was originally published on my Hashnode Blog

This article covers

  1. setAttribute , getAttribute & removeAttribute
  2. Changing Style of HTML Element
  3. kebab case, pascal case & camel case
  4. Specific way of adding, removing class to HTML Element

setAttribute

Yes, as the name suggests, this method is used to add attribute HTML element

<button  id='button'>Click </button>

<script>
let button = document.querySelector("#button");
button.setAttribute('title','Button');
</script>
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Output:
set Attribute - Binayak - Js 1o1.png

getAttribute

<button  id='button' title='button'>Click </button>
<script>
let button = document.querySelector("#button");
console.log(button.getAttribute('title')); //prints text "button" in console
</script>
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removeAttribute

<button  id='button' title='button'>Click </button>
<script>
let button = document.querySelector("#button");
button.removeAttribute('title');
</script>
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Output:

remove Attribute - Binayak - js 1o1.png

Changing Style of HTML element

Every HTML DOM have a property called style which holds the style of HTML Element

You can change the color of an HTML element by

<div id='content'> Hi There , I m Binayak </div>
<script>
let  content = document.querySelector("#content");
content.style.color="red";
</script>
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the style property of HTML is an object which holds all the style values of the element

For instance

<script>

content.style.color; //returns color
content.style.color = "blue"; //sets the color to blue

content.style.position; //returns the position of element
content.style.position = "absolute";// sets the position to absolute

</script>
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the style is accessed in the same way we set style using CSS.
But there is a little twist with the style property having two words. for example background-color

For instance

<script>
content.style.background-color = "black"; //not valid

content.style.backgroundColor = "black"; //valid
</script>
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Those property containing two words is used in kebab case in CSS but is accessed using camel case in JS.

Camel Case : nameOfPerson

the first letter capital of all words except the first word

Kebab Case : name-of-person

a hyphen - between words

Pascal Case: NameOfPerson

first letter capital of each word

Adding and removing class from HTML element

There is a property called classList in HTML element. which contains the list of class (as the name suggests)

Good thing is that property has two special methods

  1. add
<div id='content'> Hi There , I m Binayak </div>
<script>
let  content = document.querySelector("#content");
content.classList.add("primary-content");
</script>
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It adds the class primary-content to the element

  1. remove
<div id='content' class='primary-content'> Hi There , I m Binayak </div>
<script>
let  content = document.querySelector("#content");
content.classList.remove("primary-content");
</script>
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It removes the class primary-content from the element.

Note:
Using setAttribute to add class to HTML element is a bad practise.
because it removes all the previous class from the element
For instance

<div class='container' id='content'>This is a container</div>

<script>
let content = document.querySelector('content');
content.setAttribute('class','jumbotron');
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now this div has only one class i.e, jumbotron.

Be a good boy and use classList.add to add class and classList.remove to remove the class to remove unnecessary headaches in the future 😂.

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