JavaScript Fundamentals – Variables and Input Function

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What is a variable in JavaScript?

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A variable is a container for storing data values. It can hold values or expressions.

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What are the rules for naming variables in JavaScript?

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1. Must begin with a letter. 2. Case sensitive. 3. Cannot be a reserved word. 4. Cannot use special characters except underscore (_).

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What are JavaScript keywords?

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Keywords are reserved words in JavaScript that have special meaning, such as 'break', 'case', 'catch', 'function', etc.

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What are the six data types in JavaScript?

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1. Numbers 2. Booleans 3. Strings 4. Objects 5. Null 6. Undefined

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What is the difference between global and local variables?

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Global variables are accessible anywhere in the code, while local variables are only accessible within the function they are declared.

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How do you declare a global variable in JavaScript?

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By simply assigning a value to it, e.g., globalVariable = 100;

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How do you declare a local variable in JavaScript?

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By using the 'var' keyword within a function, e.g., var counter = 0;

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What is the purpose of the prompt box in JavaScript?

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The prompt box is used to get input from the user. It displays a dialog box that prompts the user for input.

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What is the syntax for using the prompt box?

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window.prompt('sometext', 'defaultText');

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How can you convert a prompt input to a number in JavaScript?

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By using the Number() function, e.g., var x = Number(prompt('Enter a number', ''));