0 == false // true
0 === false // false, because they are of a different type
1 == "1" // true, automatic type conversion for value only
1 === "1" // false, because they are of a different type
null == undefined // true
null === undefined // false
'0' == false // true
'0' === false // false
请看这里。http://longgoldenears.blogspot.com/2007/09/triple-equals-in-javascript.html
3个等号意味着"没有类型强制的平等"。使用三等号,这些值在类型上也必须是相等的。
===
和!==
是严格的比较运算符。比较运算符 - MDC