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JavaScript eval() function

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The eval() function in JavaScript is a built-in function that allows you to evaluate a string of code as if it were a JavaScript statement or block. It takes a single argument, which is the string to be evaluated.

eval(string)

JavaScript eval() function example

A simple example code passes the codeString variable as an argument to the eval() function, which evaluates it as if it were a JavaScript expression.

<!DOCTYPE html>
<html>
<body>
    <script>
    let x = 5;
    let y = 10;
    let codeString = "x + y";
    let result = eval(codeString); 

    console.log(result)
    </script>
</body>
</html>

Output:

JavaScript eval() function

Another example

let userCode = "let x = 10; let y = 20; x + y";
let result = eval(userCode); // 30

Comment if you have any doubts or suggestions on this Js basic topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version

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