Definition of undefined adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Mar 31, 2024 · Learn how to use JavaScript's `null` and `undefined` data types.

In this tutorial, you'll learn about the JavaScript undefined and how to handle it effectively.

If something is undefined it's not clear, such as your undefined vacation plans. You know you want to go somewhere during the third week of August, but you just don't know where.

un•de•fined (un′di fīnd′), adj. without fixed limits; indefinite in form, extent, or application: undefined authority; undefined feelings of sadness. not given meaning or significance, as by a …

Dec 14, 2025 · We slid into our office, past two women discussing the "X factor," an apparently undefined quality their firm felt they lacked.

Dec 10, 2024 · During my 15+ years of JavaScript experience, I‘ve seen my fair share of pesky undefined errors sinking apps in production. Trust me, no developer enjoys debugging at 2am! …

@JamiePate: Why is xyz === undefined better than typeof xyz == "undefined"? Agreed about globals, but of the two of us only you have been recommending checking properties of window.

May 7, 2009 · If you attempt to use a variable that does not exist and has not been declared, JavaScript will throw an error, var name is not defined, and the script will stop then and there. …

May 19, 2017 · The global undefined property represents the primitive value undefined. It is one of JavaScript's primitive types.

Definition of Undefined in the Definitions.net dictionary. Meaning of Undefined. What does Undefined mean? Information and translations of Undefined in the most comprehensive …

Definition of undefined adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Not defined or made clear.... Click for pronunciations, examples sentences, video.

Jul 23, 2025 · Your All-in-One Learning Portal: GeeksforGeeks is a comprehensive educational platform that empowers learners across domains-spanning computer science and …