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Jason Kang
2,749 PointsWhy won't && work for this quiz problem?? Help please
if ( username === '' password === '') { alert("Password or user name is missing"); }
So I found that the answer is || and not &&. I want to understand why && will not work. Since it says Password OR user name is missing, can't either the username and password BE true while the other be false? The username can be true and password can be false, vice-versa. In that case, true && false = false and false && true = false. Doesn't the alert in the problem mean false since it says Password or username is missing? Please help.
1 Answer
Gunhoo Yoon
5,027 PointsThis is what you were trying to do.
alert("Password or user name is missing"); //Focus on word or
If you used if ( username === '' && password === '') that would mean
alert("Password AND user name is missing"); Because in JavaScript && stands for AND.
This is how AND works, consider A && B.
A && B is true only if both A, B is true every other case evaluates to False. However,
A || B, which stands for A or B, evaluates true when A, B is true, A is true, B is true.
So in a nutshell A || B reflects more on what we meant by alert("Password OR user name is missing");
Hope you can see the difference between two.