Web Technology - Old Questions
2. How can you create objects in Javascript? Create a HTML page containing a division with image and its description in paragraph. Write a javascript function to change the value of description in the paragraph during onmouseover and mouseout event on the image.[4+6]
A javaScript object is an entity having state and behavior (properties and method). For example: car, pen, bike, chair, glass, keyboard, monitor etc. There are different ways to create new objects:
1. By using object literal: The syntax of creating object using object literal is given below:
object={property1:value1, property2:value2.....propertyN:valueN}
Example: const person = { name: 'Nisha', age: 22, hobbies: ['reading', 'singing', 'coding']};
2. By creating instance of Object directly (using new keyword): The syntax of creating object directly is given below:
objectname = new Object();
Example: const person = new Object ( { name: 'Nisha', age: 22, hobbies: ['reading', 'singing', 'coding']});
3. By using an object constructor (using new keyword): Here, we need to create function with arguments. Each argument value can be assigned in the current object by using this keyword.
Example:
function Person(name, age) {
this.name = name;
this.age = age;
}
const person = new Person("Nisha", 22);
Second part:
index.html
<!DOCTYPE html>
<html>
<head>
<title>TU</title>
<script type="text/javascript" src="web.js"></script>
</head>
<body>
<div>
<img src="images/tu.jpg" onmouseover="changeText()" onmouseout="defaultText()">
<div id="description">
<p>Department of CSIT, Tribhuvan University</p>
</div>
</div>
</body>
</html>
web.js
function changeText()
{
var display = document.getElementById('description');
display.innerHTML = "";
display.innerHTML = "Department of Computer Science and Informtion Technology, TU!! (Changed Text)";
}
function defaultText()
{
var display = document.getElementById('description');
display.innerHTML = "";
display.innerHTML = "Department of CSIT, Tribhuvan University";
}