Object Based Programming
Object-Based Programming
Everything is an object in JS. A javascript object is an entity having state and behavior. Object-based languages have the inbuilt objects. E.g., JavaScript has a window object.
There are 3 ways to create objects.
- By object literal
The syntax of creating object using object literal is given below:
object={property1:value1,property2:value2…..properyN:valueN}
Example:
<html>
<body>
<script>
emp={id:1,name:"Anil Sharma",salary:15000}
document.write(emp.id+""emp.name+""+emp.salary);
</script>
</body>
</html>
Output:
1 Anil Sharma 15000
- By creating an instance of an Object directly
The syntax of creating an object directly is given below:
var objectname=new Object();
Here,a new keyword is used to create an object.
Example:
<html>
<body>
<script>
var emp=new Object();
emp.id=1;
emp.name="Anil Sharma";
emp.salary=1500;
document.write(emp.id+""+emp.name+""+emp.salary);
</script>
</body>
</html>
Output:
Anil Sharma 15000
- By using an object constructor
Here, we need to create function with arguments. Each argument value can be assigned in the current object by using this keyword.
Example:
<html>
<body>
<script>
function emp(id,name,salary){
this.id=id;
this.name=name;
this.salary=salary;
}
e=new emp(1,"Anil Sharma",15000);
document.write(e.id+""+e.name+""+e.salary);
</script>
</body>
</html>
Output:
1 Anil Sharma 15000
Event Handling
JavaScript’s interaction with HTML elements is handled through events that occur when the user or the browser manipulates a page. When the page loads, it is called an event. Examples include events like pressing any key, closing window, or resizing a window. Event handlers are the code that invokes a specific piece of code when a particular action happens on an HTML elements.