Variables with let keyword:
===========================
Syntax:
let identifier; // variable declaration with let keyword
==> the variable with let is not to be hoisted.
That means, we can't access the variable before the definition.
==> the default value for the variable with let ==> "undefined".
==> the variable with let can able to access within the defined block but we can't extend that variable to outside the same block.
Var Vs let:
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1) The variable with var can be hoisted. But the variable with let cannot be hoisted.
2) The variable with var can access within the same block and extend to outside of the block also. Whereas the variable with let we can access within the same block but we can't extend to outside the block.
hoisting:
=========
process to extend the scope the variables/functions to above the definition.
const keyword:
==============
Syntax:
for the variable with const is:
const identifier;
Note:
the constant variable must be declared and initialized within the same line.
==> the constant variable never be hoisted.
==> Constant variable never be considered for the modification.
==> As like the let, the const keyword can able to access within the same block and cannot extend to outside the defined block.
let Vs Const:
=============
1) let can be modified
but const can't be modified.
2) let can be accessed without initialization but const cannot be accessed without initialization.
var Vs Const:
=============
1) var can be hoisted but const cannot be hoisted.
2) var can be accessed without initialization but const cannot be accessed without initialization.
3) var can have block scope and can extend to outside the block also. But const can always have only the block scope.
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IO Operations:
==============
IO ==> Input and Output
Input ==> reading of the data or accepting of the data or storing of the data
Output ==> writing of the data or printing of the data
In Java:
========
Input ==> Scanner Class
import java.util.Scanner;
main()
{
Scanner obj = new Scanner(System.in);
}
Input Operation:
================
prompt():
=========
==> using this we can read the value for the variable.
==> the prompt() can always read the value in string format.
Syntax:
identifier = prompt();
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Output Operations:
==================
alert()
=======
Syntax:
alert(value);
==> alert() can always printing anything in prompt box.
==> the alert() can always gives the content with confirmed prompt box.
confirm()
=========
Syntax:
confirm(value);
==> confirm() can always print anything in prompt box as same as the alert().
==> confirm() can give optional prompt box with data.
innerTEXT
=========
Syntax:
document.HTMLelement.innerText = "value";
==> can always print anything as web content.
==> But it cannot understand the HTML or CSS styles.
innerHTML
=========
Syntax:
document.HTMLElement.innerHTML = "value";
==> it can always nest the html content within the selected html element.
outerHTML
=========
Syntax:
document.HTMLElement.outerHTML = "value";
==> the selected html element can replace with new html content.
write()
======
Syntax:
document.write("value");
==> inline method
log()
=====
==> can always print anything on the console.
Syntax:
console.log(value);
Output Techniques