JS Comparison give unexpected result, why?

Question

var x = 5;
var y = 8;
if (x>y){
document.write(x-y);
}
else if (x=y){
document.write(x+y);
}
else{
document.write(x*y);
}
// 16
Why 16? it will be 40!

Answer 1

M. Watney HonFu Thank you man.
I was forget that.

Answer 2

Replace = with == inside else if condition.
Its actually assigning the value of y to the x, that's is, now x=8, also y=8 hence x+y=16.

Answer 3

else if (x==y)!

Answer 4

Use bitwise operators ....

Answer 5

var x = 5;
var y = 8;
if (x>y){
document.write(x-y);
}
else if (x===y){
document.write(x+y);
}
else{
document.write(x*y);
}
// not (x = y ) instead ( x === y)

Answer 6

= is for assigning variables, and == or === is to compare.
== is equal but not strict to any specific type, while === is strict to the same types on both operands.
In your case where you do,
... if(x = y) {
document.write(x+y);
} ...
You first assign the variable y which is 8 to x which previously was 5 but is now overwritten with 8.
There it writing 16 to the document.
document.write(x+y) is essentially document.write(8+8) in that case.
And second of all, assigning in an if statement, most likely always return true thus that if statement being executed.

Hope this was a pretty detailed explanation on what went code wrong cuz you accidently assigned instead of compared two values.