JavaScript/thisdemo.html at main · AnilSathi23/JavaScript · GitHub

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<!DOCTYPE html>
<html>
    <head></head>
    <body>
        <script>
            var myvar =100;
            function WhoIsThis(){
                var myvar =200;
                alert("myVar = " + myvar);
                alert("this.myVar = " +this.myvar);
            }
            WhoIsThis(); //window.WhoIsThis() also works the same way
            var obj = new WhoIsThis();
            alert(obj.myvar);

// example 2
var myvar1 = 1000;
var obj = {
    myvar1 : 3000,
    WhoIsThis:function(){
        var myvar1 = 2000;
        alert (myvar1); //2000
        alert(this.myvar1); //3000
    }
};
obj.WhoIsThis();

//call() and apply()
var demo = 100; //window Object
function  getData(){
    alert(this.demo);
}
           // demo and getdata is the obj1's property
var obj1 = {demo:200 , getdata :getData};
var obj2 = {demo:300 , getdata :getData};
getData(); // this will point to window object  so it will show 100
getData.call(obj1); // it will point to obj1  so it will show 200
getData.apply(obj2);// this will point  to obj2  so it will show 300
obj1.getdata.call(window); // this will point to window object  so it will show 100

        </script>
    </body>
</html>