JavaScript 高级程序设计（第3版）笔记——chapter3：基本概念（函数部分）

 1 function say_hello(var1, var2, var3) {
 2      var len = arguments.length;
 3      alert(len);
 4      for (i in arguments) {
 5          alert(arguments[i]);
 6      }
 7      alert(var1);
 8      alert(var2);
 9      alert(var3);
10 }
11 
12 say_hello(); //0, undefined, undefined, undefined
13 say_hello("first"); // 1, first, first, undefined, undefined
14 say_hello("first", "second", "third"); // 3, first, second, third, first, second, third
15 say_hello("first", "second", "third", "forth");// 4, first, second, third, forth, first, second, third

1 function say_hello(var1, var2, var3) {
2      for (i in arguments) {
3          arguments[i] = "change";
4      }
5      alert(var1 + var2 + var3);
6 }
7 
8 say_hello(1,2,3); //changechangechange

1 function overLoad (var1) {
2     alert("This is the first function");
3 }
4 
5 function overLoad(var1, var2) {
6     alert("This is the second function");
7 }
8 
9 overLoad(1); //This is the second function

 1 function overLoad () {
 2     if (arguments.length === 0) {
 3         alert("first");
 4     } else if (arguments.length === 1) {
 5         alert("second");
 6     } else {
 7         alert("third");
 8     }
 9 }
10 
11 overLoad(); //first
12 overLoad(1); //second
13 overLoad(1,2,3,4); //third