JavaScript - Document Object Model (DOM)

DOM = Document Object Model virtual DOM = virtual DOM hosse main DOM er upore akta alada sortcut layer, React ae sorrt cut layer kaj korte bole, main layer react nijei manipulate kore dei user k.

Document= Amra akta webpage e jakisu dekhi ta sobkisui DOM. document bolte amra MS word ja likhi take bujhi akta .text file e ja likhi take bujhi, Image=> .jpg, .png aguluo document, .pdf excel.xlsx document. amra .dot(.) diye file document er extension likhe save kori jokhon amra kono file k .html diye save korbo , atao akta document . tahole .html file er modhe ja kisu amra likhi sobi document.

Object= javaScript dot(.) document kisu chine na , sudu Object k chine, so .html file k Object akare representation korar dorkar hoi, javaScript k bujar jonno , a e bujhiye daya tai hosse DOM.

DOM hosse amader je HTML page ta asse sei page er akta Object represent kore, javaScrpt er kase, jate javaScript diye document ta k change kora jai , manipulate kora jai

Model= amra je HTML code likhi , tar first e thake , tag, tar modhe tag thake tar modhe tag thake tar modhe

tag thake tar mode

tag theke avabe.......... close hoy. Tahole ata akta hierarchical tree structure maintain korse , mane aktar por akta . a khetre at first jekono akta Object toiri kore tar akta Parent thakte hobe, to sei Parent k brower er khetre bola hoy,==== window ===== a e window hosse brower er parent ba starting point. tar modhe actually ==document== thake, tarpor HTML thake 1.first layer = Window 2.secound layer= document, webpage inspect kore ja dekhi ta hosse document 3. third layer = HTML Window = hosse global akta object. as like container, sob kisu window object er modhe thake

Tahole , window por document tar por html tag aker por ak nested akare thake, ja akta 
tree structue model er moto dekte, a e model thekei Model kotha ta assese. 
Model hosse amader je html document ase , tar akta Object representation tree Model. a e jish tai bujhano hoi DOM word diye.

//webpage first render/display hoi, //javaScript diye HTML k manipulate/poriborton kori //JavaScript active hoi brower e asar por/html browser e render/display hoyer por

//=================Sum of Two Number========================

<title>JavScript DOM</title>

<h1>Sum of Two Number</h1>
 <input id="num1"><br><br>   
 <input id="num2"><br><br>
 <button onclick="AddTwoNumber()">Add</button>   

 <script>
    function AddTwoNumber(e){
    
       let num1 = document.getElementById('num1').value;
       let num2 = document.getElementById('num2').value;
       let result=parseFloat(num1) + parseFloat(num2);

       alert(result)

       e.prventDefault();
    }
 </script>