1 var config = null;
2 undefined
3 var result = config||{};
4 undefined
5 result
6 {}
7
8 var config = undefined;
9 undefined
10 var result = config || {};
11 undefined
12 result
13 {}
14
15 var config = '';
16 undefined
17 var result = config||{};
18 undefined
19 result
20 {}
21
22 var config = 0;
23 undefined
24 var result = config||{};
25 undefined
26 result
27 {}
28
29 var config = false;
30 undefined
31 var result = config || {};
32 undefined
33 result
34 {}
35
36
37
38 var config = {name:'pine'};//'0' '1' true
39 undefined
40 var result = config||{};
41 undefined
42 result
43 {name: "pine"}
44
45
46 var result = config||{};
47 ||在此例中的作用：
48 如果config为null、undefined、''、0、false，则表达式返回{},
49 否则表达式返回config
50
51 等同于：
52 function nvl(config){
53 if(config==null||config==undefined||config===''||
54 config===0||config===false){
55 return {};
56 }
57 return config;
58 }
