1、In mathematics, programming and related fields, "undefined" stands as an intrinsic concept reflecting an indeterminate state without an assigned, applicable or computable value， In mathematics, a term, process or state can be deemed undefined following noncompliance with fundamental rules. Contrarily, in computer programming, the term "undefined" underscores the absence of a specific value or function.
2、 Also, JavaScript’s interpreter will output “undefined” when it encounters a variable or object property that isn’t assigned a value. “Undefined” does not suggest a void or absences but rather a fundamental violation of the system’s rules， A variable, program or software may remain undefined because the programmer forgot to assign a value or a function. These instances may include division by zero, the tangent of a right angle or extending a real number system by a null element without violating the laws of arithmetic， Consequently, despite appearing as a negative or passive term, "undefined" often underscores a critical requirement for system logic, hoping to prevent takings actions that are not allowed or do not make sense in a specified context, serving to uphold the integrity of rigorous mathematical principles or the operating parameters of programming languages and systems. These scenarios typically yield the "undefined" error message， Even though it’s quite paradoxical, undefined in computer science doesn’t necessarily connote oversight or system failure but can be tactically leveraged by developers to mark a missing element or temporarily hold a place without assigning a certain value.
