JavaScript Functions

Simple Example
It defines a function called sayHello that takes no parameters
• Calling a Function
• To invoke a function somewhere later in the script, you would simply
need to write the name of that function as shown in the following
code.

Function Invocation
The code inside the function will execute when
"something" invokes (calls) the function:
When an event occurs (when a user clicks a button)
When it is invoked (called) from JavaScript code
Automatically (self invoked)

Function Return
The code inside the function will execute when
"something" invokes (calls) the function:
When an event occurs (when a user clicks a button)
When it is invoked (called) from JavaScript code
Automatically (self invoked)

Why Functions?
You can reuse code: Define the code once, and use it many times.
You can use the same code many times with different arguments, to
produce different results.

The () Operator Invokes the Function
toCelsius refers to the function object, and toCelsius() refers to the
function result.
Accessing a function without () will return the function object instead
of the function result.

String in Javascript
 The JavaScript string is an object that represents a sequence of
characters.
 There are 2 ways to create string in JavaScript
 By string literal
 By string object (using new keyword)

1) String Literal
 The string literal is created using double quotes.
 Syntax
var stringname="string value";
<html>
<body>
<script>
var str="This is string literal";
document.write(str);
</script>
</body>
</html>

2) By string object (using new keyword)
Syntax
var stringname=new String("string literal");
Here, new keyword is used to create instance of string.
<html>
<body>
<script>
var stringname=new String("hello javascript string");
document.write(stringname);
</script>
</body>
</html>

JavaScript Functions

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