<!DOCTYPE html>
<html>
<head lang="en">
<meta charset="UTF-8">
<title></title>
</head>
<body>
<script>
//fn1(1, 2, 3, 5);
function fn1() {
alert(arguments) // object
alert(arguments.length) // 4
alert(arguments[arguments.length - 1]) // 5
}
// 课后小练习：
alert(sumOrSub(1, 2, 3, '+')); // 6
alert(sumOrSub(10, 2, 3, 4, '-')); // 1
function sumOrSub() {
var total = 0;
var flag = arguments[arguments.length - 1];
switch (flag) {
case '+' :
for (var i = 0; i < arguments.length - 1; i++) {total += arguments[i];} break;
case '-' :
for (var i = 1; i < arguments.length - 1; i++) {total += arguments[i];}
total = arguments[0] - total;
break;
case '*' : break;
case '/' : break;
}
return total;
}
</script>
</body>
</html>
