What is the difference between these two statements?
if (typeof errorMessage !== undefined)
{}
and
if (typeof (errorMessage) !== undefined)
{}
One of them has a pair of entirely superfluous parentheses.
The difference between typeof foo
and typeof (foo)
is the same as the difference between 1 + 1
and (1) + (1)
.
An an aside, the typeof
operator will give you a string, so you should be comparing to "undefined"
not undefined
.
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.