javaScript-course--zero-to-hero/16-callBack-functions.html at main · codingwithsaleem/javaScript-course--zero-to-hero · GitHub

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<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>call back functions</title>
</head>

<body>
    <script>
        //first example for callBack function
        //you can pass inside another function as a parameter this is call callBack function.

        // function add(a, b, callBack) {
        //     console.log(a + b);
        //     callBack();
        // }

        // function sayHello() {
        //     console.log("hello every one")
        // };
        // function sayHI() {
        //     console.log("its call back function")
        // }
        // add(5, 8, sayHI)
        // add(7, 9, sayHello)
        // //using anonymous function (means unknown name)
        // add(7, 9, function () {
        //     console.log("this is anonymous function means without name")
        // })

        //second example of callBack function using asynchronus:

        function loadScript(url, callBack){
            let script=document.createElement("script")
            script.src=url;
            document.body.appendChild(script);
            script.onload=function(){
                callBack(null,url);

            }
            script.onerror=function(){
                callBack(new Error("src got some error "));
            }
            }


        function onLoad(src){
            console.log("script is loded successfully.. " +src)
        }
        function onError(error,src){
            if (error){
                console.log(error)
                return;
            }
            else{
                console.log("your url run succesfully ")
            }

        }
        loadScript("https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/js/bootstrap.bundle.min.js" ,onLoad);


    </script>
</body>

</html>