Let and const Variable JavaScript Tutorial in Hindi

Example with var

<script>    
    /*in this example 
      1. Multiple time declare variable
      2. multiple time assign value*/
    var a = "Teach";
    var a = "Coders";
    a = "Hello Teach Coders";
    console.log(a);

    /*Example of funcation scope
      1. This is Global scope
    */
    myfun(true);
    function myfun(x){
      var h = "hello";
      if (x == true){
        var fn = "Teach";
        var ln = "coders";    
        // here "fn" variable & "ln" variable value access so this is global scope     
      }
      console.log(h+" "+fn+" "+ln);
      // here "fn" variable & "ln" variable value access so this is global scope    
      
    }
</script>
 

Example with let 
 



<script>    
    /*in this example 
      1. singale time declare variable
      2. multiple time assign value*/
    let b = "Teach";
    b = "coders";
    b = "hello Teach Coders"
    console.log(b);

    /*Example of funcation scope
      1. This is block scope
    */
   myfun(true);
    function myfun(x){
      let h = "hello";
      if (x == true){
        let fn = "Teach";
        let ln = "coders";  
        console.log(h+" "+fn+" "+ln); 
        //console.log(h+" "+fn+" "+ln); onlye here we can access so this is local scope or block scope    
      }
      //console.log(h+" "+fn+" "+ln); here we can't access so this is local scope or block scope    
    }
</script>
 

Example with Const 
 



<script>    
    /*in this example 
      1. singale time declare variable
      2. singale time assign value*/
    const c = "Teach"
    console.log(c)

    /*Example of funcation scope
      1. This is block scope
    */
   myfun(true);
    function myfun(x){
      const h = "hello";
      if (x == true){
        const fn = "Teach";
        const ln = "coders";  
        console.log(h+" "+fn+" "+ln);
        //console.log(h+" "+fn+" "+ln); here we can access so this is local scope or block scope    
      }
      //console.log(h+" "+fn+" "+ln); here we can't access so this is local scope or block scope
      
    }
</script>