JavaScript ❤️




Why Study JavaScript?

JavaScript is one of the 3 languages all web developers must learn:
   1. HTML to define the content of website pages
   2. CSS to specify the layout of website pages
   3. JavaScript

 


JavaScript Can Change HTML Content:

One of many JavaScript HTML methods is getElementById().
This example uses the method to "find" an HTML element (with id="demo") and changes the element content (innerHTML) to "Hello JavaScript":

Example:


document.getElementById("demo").innerHTML = "Hello JavaScript"; 

JavaScript Can Change HTML Attribute Values:

In this example JavaScript changes the value of the src (source) attribute of an <img> tag:

The Light Bulb


JavaScript Can Change HTML Attribute Values

In this example JavaScript changes the value of the src (source) attribute of an <img> tag:

TURN OFF

AFTER CLICK ON BUTTON image change to on bulb.


TURN ON




JavaScript Can Change HTML Styles (CSS)

Changing the style of an HTML element, is a variant of changing an HTML attribute:

Example:


document.getElementById("demo").style.fontSize = "35px";


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