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How To Use ChatGPT for A/B Testing

Donald Ng
March 21, 2024
5-star rating
Reviews on Capterra

As a CRO professional, you understand the importance of A/B testing in optimizing your website’s performance. However, implementing new test variants often requires technical expertise in JavaScript and CSS, which can be a challenge for those without a development background.

Fortunately, with the help of ChatGPT, you can now take care of the technical aspects of creating test variants, even if you don’t have extensive coding knowledge.

Why Learn the Basics of JavaScript and CSS

While ChatGPT can generate custom JavaScript and CSS code for your test variants, it’s essential to have a basic understanding of these languages to ensure the code is implemented correctly and safely.

By learning the fundamentals of JavaScript and CSS, you can:

  1. Communicate more effectively with developers
  2. Quickly prototype and test new ideas
  3. Troubleshoot issues independently
  4. Implement minor changes without waiting for developer assistance

Using ChatGPT to Generate JavaScript Snippets

One of the most powerful features of ChatGPT is its ability to generate code based on natural language prompts. CRO professionals can use a templated prompt to ask ChatGPT to create a JavaScript snippet for their test variant.

Here’s an example prompt:

Please generate a JavaScript snippet for my website A/B test that does the following:
1. Add click event to main call to action button to send an event with name "cta_click" to GA4/GTM
2. Change the button text to "FREE Full Access"

CSS Selector to the button: .btn.btn-primary

The last line to CSS Selector is optional and you can learn how to access this information from the video on the next section.

Here is the result to this prompt which you can just directly copy the output and used it as a Custom JS code for your test variant.

By providing ChatGPT with the necessary information, such as the CSS selector, new text content, and custom event name, you can quickly generate a JavaScript snippet for your test variant.

Check out this video demonstration to see how it works:

Understanding the Generated Code

While ChatGPT is a powerful tool for generating custom JavaScript and CSS code, it’s essential for CRO professionals to understand the code they are implementing. Without a basic understanding of the generated code, CRO specialists may be hesitant to use it in their A/B tests.

To help bridge this gap, let’s cover some basics of CSS selectors and how they are used in JavaScript and CSS.

CSS Selectors

CSS selectors are used to target specific elements on a web page for styling or manipulation. Some common CSS selector types include:

  1. Element selectors (e.g., button, p, div)
  2. Class selectors (e.g., .button, .text-red)
  3. ID selectors (e.g., #main-cta, #header)
  4. Attribute selectors (e.g., [type="submit"], [data-id="123"])

In JavaScript, you can use methods like querySelector() and getElementsByClassName() to target elements based on their CSS selectors. For example:

const button = document.querySelector("#main-cta");
const elements = document.getElementsByClassName("text-red");

In CSS, you can use these selectors to apply styles to specific elements:

#main-cta {
 background-color: #ff0000;
 color: white;

.text-red {
 color: red;

Inspecting Elements in Modern Browsers

To effectively use CSS selectors, you need to be able to identify the appropriate selectors for the elements you want to target. Modern browsers like Google Chrome and Mozilla Firefox have built-in developer tools that allow you to inspect elements and find their CSS selector paths.

Here’s a step-by-step guide on how to inspect elements using Google Chrome:

  1. Right-click on the element you want to inspect and select “Inspect” from the context menu.
  2. The developer tools will open, and the selected element will be highlighted in the “Elements” tab.
  3. Right-click on the highlighted element in the “Elements” tab and select “Copy” > “Copy selector”.
  4. The CSS selector path for the element will be copied to your clipboard, ready to be used in your JavaScript or CSS code.

Using ChatGPT with A/B Testing Tools

Many A/B testing tools, such as, offer custom JavaScript features that allow you to manipulate test variants directly within the tool. By combining the power of ChatGPT with these custom JavaScript features, CRO professionals can easily create and implement test variants without relying on external developers.

For example, using’s custom JavaScript feature, you can paste the code generated by ChatGPT directly into the tool to create your test variant. This streamlines the A/B testing process and empowers CRO professionals to take control of their experiments.

Understanding Basic JavaScript Concepts

To further enhance your ability to create test variants using ChatGPT, it’s helpful to understand some basic JavaScript concepts, such as for loops and event listeners.

For Loops

For loops allow you to iterate over a collection of elements and perform actions on each element. For example, if you want to change the text of multiple buttons with a shared CSS class, you can use a for loop:

const buttons = document.getElementsByClassName("shared-class");

for (let i = 0; i < buttons.length; i++) {
 buttons[i].textContent = "New Button Text";

Event Listeners

Event listeners allow you to trigger actions based on user interactions, such as clicks. You can use the addEventListener() method to attach click event listeners to elements. For example:

const button = document.querySelector("#main-cta");

button.addEventListener("click", function() {
 // Perform action when the button is clicked

You can also use ChatGPT to generate code snippets that include event listeners for multiple buttons with a shared attribute, triggering Google Analytics events or events when clicked.

The Future of CRO with AI

The rise of AI tools like ChatGPT is transforming the CRO industry, empowering professionals to create and implement test variants without relying on third-party developers. As AI continues to advance, we can expect to see even more powerful tools and techniques emerge, enabling CRO professionals to optimize their websites more efficiently and effectively.

By embracing AI and learning the basics of JavaScript and CSS, CRO professionals can stay ahead of the curve and deliver better results for their clients and businesses.

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