The Best Practices for JavaScript Security

By Hardik Savani October 26, 2023 Category : Guest Post

Do you have an interactive app or website? If so, JavaScript security is a leading priority as there are diverse types of things, from programmatic mistakes and unforeseen user inputs to spiteful assaults. Moreover, JavaScript Security consists of innumerable streams restoring the needs for software development.

JavaScript is renowned for providing cross-browser compatibility. Are you wondering about the best practices for JavaScript security?

In this article, we will help share precious knowledge on efficient strategies and elementary principles to strengthen your JavaScript code, nurturing a highly flexible online landscape.

JavaScript Security: Overview & Example

Before proceeding with the best practices, let us give you an example of a globally renowned airline: British Airways encountered a harsh cyber-attack. Magecart is a group that intruded on the company's website, and these malicious hackers exploited a JavaScript susceptibility on their payment page.

As an outcome, approx. Three hundred eighty thousand customers fell prey to this hacking scene, where their financial and personal data was breached. This example of British Airways demonstrated an insecure JavaScript security, which needs to be bolstered.

It has been surveyed by Stack Overflow in 2022 that JavaScript is widely used by 67.9% of professional software developers. Despite JavaScript's ubiquitous adoption and significant utilization, it unfortunately poses a major safety issue.

6 JavaScript Security Best Practices

With the help of these best JavaScript security practices, you can safeguard yourself and your customers, can get rid of typical susceptibilities, and thwart spiteful assaults against your website.

1. Encode confidential data in transition

One of the best practices for JavaScript security is to protect sensitive or confidential data at rest and in transition. You may encode data using a bolstered encrypted algorithm, and the best way to utilize this encryption is to add an SSL certificate for your installed JavaScript application. The SSL certificates safeguard communication between the web browser and the user's device via cryptographic encryption.

Therefore, you should buy SSL certificate from CA (certificate authority) to ensure maximum credibility among users, and this process of SSL certificate includes the CSR generation and all the details of the requester. After submitting the CSR, the CA performs the validation process, and once it is over. The CA issues the SSL certificate, which can be installed on the JavaScript app.

2. Never trust user input

Often, the web application permits users to include data via text input, and once the data is added, it has reflected somewhere in the web app. However, embracing and showcasing inputs from the users beget cross-site scripting assaults in which hackers utilize special characters to deceive browsers into elucidating text as JavaScript code or HTML markup. However, in order to mitigate these cross-site scripting attacks, you must sanitize inputs along with applying output encryption.

3. Employ a CSRF token, which isn't preserved in cookies

Do cookies drive your application's user authentication? If so, your session cookies are vulnerable to assault from a hostile party, who may then use them to represent an authorized user. The CSRF assaults are one of the most common JavaScript security susceptibilities, and you can quickly thwart this issue by sending an extra token with the HTTP request.

Attackers or cyber criminals cannot access them as the CSRF token is not preserved in cookies. Do not forget to incorporate CSRF tokens into AJAX calls, concealed fields, forms, HTTP headers, etc.

4. Crosscheck your apps religiously

App testing is vital for your code's safety against cyber assaults. Therefore, you must examine the applications as per the transforming definitions of cyber-attacks and hazards. You need to ensure maximized vulnerability penetration and scanning for optimum JavaScript security.

Nevertheless, testing activity may get enormous at scale, which is why the best practice of JavaScript is to take advantage of automation. It lets you mitigate manual testing jobs and concentrate on app development.

5. Keep updating dependencies and libraries

JavaScript projects count significantly on third-party packages and libraries. Such types of dependencies, if not updated daily, might become safety vulnerabilities themselves. An obsolete library might have uncompensated safety issues that hackers can make use of. All you need to do is update the dependencies daily and eliminate unutilized libraries to lower the attack surface.

To find out and fix unprotected dependencies, you may use tools, including GitHub's Dependabot or npm audit. While you select library, always prioritize actively maintained ones with a bigger user base, they will have minimal safety flaws and will be fixed instantly if issues arise.

6. Employ a CSP, aka Content Security Policy

Whenever web browsers install HTML content, the images from audio, CDN, and video might be installed from other domains, too. A browser cannot ascertain if any of the requests are unforeseen.

However, a CSP is an additional safety layer that helps eliminate cross-site scripting and other assaults. The domains from which content is obtained and the protocols used can both be restricted by CSPs.

Additionally, they can impose restrictions on the performance of embedded scripts, event controllers, and functions like eval and Function that can interpret strings as code. CSPs possess several norms. Therefore, you must know their indications, assess which guidelines must be used, turn them on, and evaluate report infringements.


The strategies used by hackers to carry out cyberattacks change annually. Because of this, you must be confident that your JavaScript programs can withstand intrusions and protect data. Here, we have covered the top six JavaScript security recommendations. The one you should pick, nevertheless, will rely on your app's specific company demands.

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