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How does input sanitization work in JavaScript?

Asked on Aug 25, 2025

Answer

Input sanitization in JavaScript involves cleaning user input to prevent malicious data from causing harm, such as cross-site scripting (XSS) attacks. This is typically done by removing or escaping potentially dangerous characters.

<!-- BEGIN COPY / PASTE -->
        function sanitizeInput(input) {
            const element = document.createElement('div');
            element.innerText = input;
            return element.innerHTML;
        }

        const userInput = "<script>alert('XSS');</script>";
        const safeInput = sanitizeInput(userInput);
        console.log(safeInput); // Outputs: &lt;script&gt;alert('XSS');&lt;/script&gt;
        <!-- END COPY / PASTE -->

Additional Comment:

The "sanitizeInput" function creates a temporary "div" element and sets its "innerText" to the user input, which automatically escapes HTML special characters.
This method is useful for preventing XSS by converting potentially harmful HTML tags into harmless text.
Always validate and sanitize all user inputs, especially if they are used in HTML or stored in a database.

✅ Answered with JavaScript best practices.

Ask any question about JavaScript here... and get an instant response.

How does input sanitization work in JavaScript?

Asked on Aug 25, 2025

Answer

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