JavaScript Basic notes 3.
Functions In JavaScript...
Q.1) Functions in Javascript
Ans. If we have more line codes and it was reusable many times then we can store on it a function and when we want to use these codes then we call the function name simply and our code were run.
If we have a big amount of apples and in future, we keep them in another place then we took these apples into a box and keep it in another place.
Syntax:
function function_name(){
// statement
}
Let's see an example 👇
Remember one thing when you create a function after creating it is necessary to call it. like the upper image, I call a function in 4th line [myfun()]
Q.2) Function with Parameters.
Ans. If the function work is the same but we want to minor changes in the function then we need to use parameters in a function.
Syntax:
function function_name(parameter1,parameter2,.......){
// statement...
}
function_name(values);
Let's see with an example👇
Q.3) Function with the return value.
Ans. If we want to not perform a code(like adding, sub, multiplication) into the function we can use a return statement in the function. If we want to reuse the code then we use the return statement.
Syntax:
function function_name(perameter1,perameter2,.....){
//statement
return value
}
function_name(values);
Let's see with an example👇
Q.4) Global and local variables.
Ans. Global variables are declared outside the function and the local variables are declared inside the function.
Difference between Global and Local variables
Global variables:- Global variables work inside the function and outside the function.Local Scope:- Local variables don't work on outside the function. It only works inside the function.
Q.5) Events In JavaScript.
Ans. Basic events list:-
Click
Double Click
Right Click
Mouse Hover
Mouse Out
Mouse Down
Mouse Up
Key Press
Key Up
Load
Unload
Resize
Scroll
Q.6) Loops in JavaScript.
Ans. The basic definition of a loop is to print the statement continuously and give it several times. There are five types of loops In JavaScript which are following as:
while Loop
Do/while loop
for loop
for in loop --> This is used with OBJECT.
forEach loop --> This is used with Array
While loop Syntex:
var a = 1 --> initialization
while(a <=10){ ---> Condition
console.log("hurry");
a=a++ ---> increment/decrement
}
Let's see with an example👇
Do while loop Syntax;
let a = 1; ---> Initialization
do{
console.log(a);
a = a++; ----> Increment/decrement
}while(a<=5) ----> condition
Let's see with an example 👇
For loop Syntax in JS
for(let a = 0; a<=10;a++){
console.log(a)
}
Let's see with an example 👇
If you want to read more about loop then click on this link.
Q.7) Break and Continue In JS
Ans. This statement runs in conditional statements like we are running a loop statement and if we want to break a specific condition we use a break statement.
Syntax:
for (initialization;condition;increment/decrement){
//condition with if else
//statement
break/continue
}
console.log("message")
Let's see with an example👇
This is for continuing statement👆
This is for the Break statement👇
