节选自《The Definitive guide,5th Edition》, 总是记不住，还是找个地方存着。。。
|
Value
|
Context in which value is used
|
|||
|
|
String
|
Number
|
Boolean
|
Object
|
|
Undefined value |
"undefined" |
NaN |
false |
Error |
|
null |
"null" |
0 |
false |
Error |
|
Nonempty string |
As is |
Numeric value of string or NaN |
TRue |
String object |
|
Empty string |
As is |
0 |
false |
String object |
|
0 |
"0" |
As is |
false |
Number object |
|
NaN |
"NaN" |
As is |
false |
Number object |
|
Infinity |
"Infinity" |
As is |
true |
Number object |
|
Negative infinity |
"-Infinity" |
As is |
TRue |
Number object |
|
Any other number |
String value of number |
As is |
true |
Number object |
|
true |
"true" |
1 |
As is |
Boolean object |
|
false |
"false" |
0 |
As is |
Boolean object |
|
Object |
toString( ) |
valueOf( ), toString( ), or NaN |
true |
As is |
