test222.html

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>

<head>
    /*CSS部分*/
    <style>
        .box1 {
            width: 400px;
            height: 300px;
            background: pink;
            /* border-top: 10px solid rebeccapurple; */
            /* overflow:hidden; */
            padding-top: 100px;
            /* box-sizing: border-box; */
            position: relative;
        }

        .box2 {
            width: 100px;
            height: 100px;
            background: lightblue;
            position: absolute;
            left: 0;
            top: 0;
        }
        .box3{
            height: 100%;
            width: 200px;
            background: seagreen;
        }
    </style>

<body>
    <div class="box1">
        <div class="box2">
        </div>
        <div class="box3">

        </div>
    </div>
    <script>

        // function add(a){
        //     function sum(b){
        //         a += b
        //         return sum
        //     }
        //     sum.toString = function(){
        //         return a
        //     }
        //     return sum
        // }
        
        function add(...params1){
            let total = 0
            for(let i=0;i<params1.length;i++){
                total += params1[i]
            }
            function sum(...params2){
                for(let i=0;i<params2.length;i++){
                    total += params2[i]
                }
                return sum
            }
            sum.toString = function(){
                return total
            }
            return sum
        }


        console.log(add(1));             // 1
        console.log(add(1)(2));      // 3
        console.log(add(1)(2)(3));// 6
        console.log(add(1)(2, 3)); // 6
        console.log(add(1, 2)(3)); // 6
        console.log(add(1, 2, 3)); // 6



    </script>
</body>

</html>