JS two identical strings are judged to be unequal.

Today in writing JS, encountered a strange problem, obviously two strings equal, with alert () print out all the same, typeof the result is a string,

Look carefully, there are no spaces.

But judging by a==b is not equal.

Later on the Internet to check the information,

Although the two strings look no different from the naked eye, they may not be the same after processing with encodeuricomponent () (I have found a string preceded by a%EF%BB%BF and the other is not)

Workaround: A.trim () = = B.trim ()

JS two identical strings are judged to be unequal.