What would be the outcome of trying to access an undefined variable in JavaScript?

When attempting to access an undefined variable in JavaScript, the outcome is that it returns undefined. In JavaScript, if you try to access a variable that has not been declared or initialized, the language does not throw an error; instead, it returns a special value called undefined. This indicates that the variable exists but has not been assigned a value.

The behavior of JavaScript allows developers to check whether a variable has been assigned a value by simply inspecting its value. If the variable is indeed undeclared, accessing it will still yield undefined, which can be useful in certain contexts, such as checking for the existence of an optional variable.

This characteristic is part of JavaScript's flexible and dynamic nature, which allows for variables to be declared and used differently compared to other programming languages that may enforce stricter variable declarations.