公司技术群里发了个问题：
js中 ""==0的返回值是什么。当然，js老手们大部分是知道返回true。这时候，晓东大侠贴了这么一段，果断收藏。
11.9.3 The Abstract Equality Comparison AlgorithmThe comparison x == y, where x and y are values, produces true or false. Such a comparison is
performed as follows:
1. If Type(x) is different from Type(y), go to step 14.
2. If Type(x) is Undefined, return true.
3. If Type(x) is Null, return true.
4. If Type(x) is not Number, go to step 11.
5. If x is NaN, return false.
6. If y is NaN, return false.
7. If x is the same number value as y, return true.
8. If x is +0 and y is −0, return true.
9. If x is −0 and y is +0, return true.
10. Return false.
11.If Type(x) is String, then return true if x and y are exactly the same sequence of characters (same
length and same characters in corresponding positions). Otherwise, return false.
12. If Type(x) is Boolean, return true if x and y are both true or both false. Otherwise, return false.
13.Return true if x and y refer to the same object or if they refer to objects joined to each other (see
13.1.2). Otherwise, return false.
14. If x is null and y is undefined, return true.
15. If x is undefined and y is null, return true.
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16.If Type(x) is Number and Type(y) is String,
return the result of the comparison x == ToNumber(y).
17.If Type(x) is String and Type(y) is Number,
return the result of the comparison ToNumber(x) == y.
18. If Type(x) is Boolean, return the result of the comparison ToNumber(x) == y.
19. If Type(y) is Boolean, return the result of the comparison x == ToNumber(y).
20.If Type(x) is either String or Number and Type(y) is Object,
return the result of the comparison x == ToPrimitive(y).
21.If Type(x) is Object and Type(y) is either String or Number,
return the result of the comparison ToPrimitive(x) == y.
22. Return false.