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Audra Ogilvy
Audra Ogilvy
3,142 Points

Using the var keyword versus just using =

In JavaScript, is there a difference between a variable created using the var keyword, and a variable created just with the equals operator? In other words, is this: var guess = false different than this: guess = false ?

1 Answer

Steven Parker
Steven Parker
229,967 Points

It depends on where it is done.

In global scope, they are the same. But in a function, "var" creates a variable limited to the scope of the function, but an implicit declaration creates (or alters) a global variable.

But implicit declarations are not considered good programming practice, and when the system is in "strict" mode, they are not allowed at all and cause an error.