Check if a variable exists in JavaScript Subash Chandran 24th September 2020 Leave a Comment Find out how to find out if a variable exists in JavaScript. var num = 20; if(num !== undefined && num !== null) { document.write("Variable 'num' exists"); } Curly hair, very fair, please share 🙂Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Telegram (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to email this to a friend (Opens in new window) Solutions Check if a File exists in C#, Check if a file exists in Java, Check if MongoDB database exists?, How can I check if a JavaScript variable is function type?, How do I check if a Python variable exists?, How to check if a file exists or not in Java?, How to check if a key exists in a Python dictionary?, How to check if a MySQL database exists?, How to check if a python module exists without importing it?, how to check if a variable is an array in javascript, How to check if a variable is an integer in JavaScript?, How to check if a variable is boolean in JavaScript?, How to check if a variable is NaN in JavaScript?, How to check if an alert exists using WebDriver?, How to check if an item exists in a C# array? Change font size A Decrease font size. A Reset font size. A Increase font size.