How to create JS Functions

Shahaparan — Thu, 23 Nov 2017 17:10:08 +0000

javascript ,Reactjs, nodejs,vuejs

something about function

Function means "Building Blocks" of the program . It can allow to reuse the code without repetition. For Example , we need to create shopping cart . To get AddItemCart , total-amount . It is used for the program .

Let's talk about function . How to create Functions.

Function Declaration:

function Createfunction(){
alert("Hello world!");
}
Createfunction();

Let's explain the code . "function" is keyword which have to write first then I create function Name which can be wrote any-letter and The parameters will be the brackets(empty in the example above) . Finally, Function body code where you have to write your all codes .

Createfunction() is called for function output . If you write two times, the output will show two times . it executes the code of the functions.

Local variable:

Local variable declared inside the function body is only visible that function . Make sure that when You will write the title of function name , You can write the first letter of word can be capital letter because it will help you to see look nice .. Example:CreateMyName. In addition, I will write later how to write properly the name of function.

Example:1

function CreateMyName(){
var name = "poran";
alert(name);
}

CreateMyName(); // output : poran
alert(name); // Error output because Variables is called as a local .

outer Variable:

outer variable declared outside of the function .
Example:2

var name = "poran";
function ShowName(){
var nickName = "Shaha" + name;
alert(nickName);
}

ShowName(); // output : Shahaporan

Outer variable is worked as global variables.It has full accessed and modify in the code .

Example:3

var name3 = "poran"; // outerVariable
function ShowName(){
name3 = "Sujon"; // Outer variable is changed .
var nickName = "My Name is" + name3;
alert(nickName);
}
alert(name3); // Show outer value
ShowName(); // output : My Name is Shahaporan
alert(name3) // Show changed value

Here is missing something about outer variables that I will write next articles .

"Happy coding"

DEV Community: Shahaparan

How to create JS Functions

Function Declaration:

Local variable:

outer Variable: