function/js_function01_0606.html

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    <title>Document</title>
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    <script>

        //function
        //function 先宣告

        //function sayHello(){
        //    document.write('Hello<br>');
        //}

        //呼叫:
        //sayHello();
        //sayHello();
        //sayHello();
        //sayHello();
        //sayHello();
        //sayHello();

        //note:養成良好習慣先宣告再使用

        //function 丟在變數
        //let myFunction = function() {
        //    document.write('Hi<br>');
        //};
        //console.log(myFunction);

        //myFunction();
        //myFunction();
        //myFunction();

        //functiono放名字的方式
        //function(name)

        //function sayHelloName (name='Jenny'){
        //    document.write(`HELLO ${name}<br>`)
        //}

        
        //sayHelloByName('Annie');
        //sayHelloByName('Bonnie');
        //sayHelloByName('Cathy');
        //sayHelloByName();


        //return value function 方式
        function sum(num1,num2){
            return num1 + num2; //如果有碰到return 這個執行後 下面的程式就不會執行
            return num1 - num2;
            return num1 * num2;
            return num1 / num2;
        }

        let result = sum(5,10);
        console.log(result);


        //有參數的function return練習 (用let myFunction)
        let myFunction3 = function (num1,num2) {
            return num1 * num2; //程式只要碰到retun 下面程式就不會執行
        }

        let myFun3Result = myFunction3(5,4);
        console.log(myFun3Result);

        //箭頭函式只有在JavaScript有 function改成=>
        let arrowFun =  (num1, num2) => num1 * num2;
        let result1 = arrowFun(10,20);
        let result2 = arrowFun(10,30);
        console.log(result1);
        console.log(result2);
        

    </script>


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