Content Replacement Script for A/B Testing on Your Website

If you are a marketer or SEO specialist, you know how important it is to regularly test hypotheses: headlines, images, calls to action, and forms that influence user behavior and conversion.

But launching A/B tests often runs into technical issues. You need to edit code, wait for developer support, coordinate changes with IT—so the test either gets postponed or only one version runs every six months.

The QForm replacement script solves this problem. It updates content directly in the user's browser, without server-side edits or involving developers. All you need to do is connect the script, create a file with variants (channel.json), and place it on your website.

Content is replaced automatically. The user sees only the version assigned by the system, and the data is immediately sent to Yandex.Metrica.

Search engines see only the original content, because the replacement happens after the page loads. This makes the tool SEO-safe.

How It Works: From Script to Replacement

The QForm script checks which test group the user belongs to and, based on predefined rules, inserts the appropriate content into specified elements on the page.

To make everything work correctly, follow these three steps:

Connect the Script

Add this line in <head> or before </body>:

Content Replacement Script for A/B Testing on Your Website

If you are a marketer or SEO specialist, you know how important it is to regularly test hypotheses: headlines, images, calls to action, and forms that influence user behavior and conversion.

Content is replaced automatically. The user sees only the version assigned by the system, and the data is immediately sent to Yandex.Metrica.

Search engines see only the original content, because the replacement happens after the page loads. This makes the tool SEO-safe.

How It Works: From Script to Replacement

The QForm script checks which test group the user belongs to and, based on predefined rules, inserts the appropriate content into specified elements on the page.

To make everything work correctly, follow these three steps:

Connect the Script

Add this line in <head> or before </body>:

html

<script defer src="https://storage.yandexcloud.net/script/channel/channel.js"></script>

Specify Elements on the Page

Your page has HTML blocks where you want to insert different content versions. Simply assign them clear CSS classes.

Example:

html

<div class="text-1">Default headline</div>
<div class="text-2"><img src="default.jpg"></div>

The script will find all blocks with classes text-1 and text-2 and replace their content with the corresponding values from the configuration. You define class names yourself—just make sure they match the keys in the JSON file.

Create the channel.json File

Once classes are defined, configure the actual variants in the channel.json file placed at the root of your site.

Example:

json

{
  "yandexCounterId": 123456789,
  "channels": {
    "variant-a": {
      "text-1": "Headline for Variant A",
      "text-2": "<img src='https://site.ru/banner-a.jpg'>"
    },
    "variant-b": {
      "text-1": "Headline for Variant B",
      "text-2": "<img src='https://site.ru/banner-b.jpg'>"
    }
  }
}

Key points:

yandexCounterId – the Metrica counter ID to send events by variant name.
channels – a list of all test variants.
text-1, text-2 – keys matching CSS classes on the page. The values are the HTML to be inserted.

The file can include any number of variants and blocks. You can insert not only text but also HTML: images, forms, buttons, iframes, video widgets, etc.

Now that you understand the system structure, let’s explore which elements you can test and how it works in practice.

What You Can Test: A/B Replacement Examples

The QForm script gives you complete freedom to experiment with any on-page elements to see what really works for your audience. Here are practical A/B test ideas:

Headlines

Test which wording grabs attention better:

json

"text-1": "Buy before the weekend ends"

json

"text-1": "20% off today only"

This type of A/B test helps quickly find which version gets more clicks or keeps users engaged longer.

Images and Banners

Compare visuals that may affect first impressions. Great for rotating banners where each user sees a different version within the same test:

json

"text-2": "<img src='img/banner-a.jpg'>"

json

"text-2": "<img src='img/banner-b.jpg'>"

Buttons and CTAs

Try different button texts or designs:

json

"text-3": "<button class='btn'>Get an offer</button>"

json

"text-3": "<button class='btn'>Check price</button>"

QForm Forms

Show different form versions: with video, without, with varying lengths:

json

"text-4": "<div data-formid='form_a'></div>"

json

"text-4": "<div data-formid='form_b'></div>"

Videos and Widgets

Test greetings, explanations, demos:

json

"text-5": "<div data-widget='videowidget_a'></div>"

json

"text-5": "<div data-widget='videowidget_b'></div>"

All replacements are tracked as goals in Yandex.Metrica. You can clearly see which versions perform best—by views, clicks, form submissions, and other actions.

Now let’s look at how the script integrates with other QForm tools to enhance automation and analytics.

How the Script Works with QForm

One of the biggest advantages of the script is that it integrates perfectly with other QForm tools. This lets you build a full funnel—from display to lead generation and CRM integration.

Example Process:

The user visits the site and is assigned variant A or B.
The script inserts the relevant content: text, banner, or form.
The visitor fills out the QForm form.
The system automatically passes the segment to the form (via cookie or UTM).
The lead is sent to the CRM, and you immediately see which variant it came from.
Metrica logs a goal with the variant name.

As a result, you get clear analytics and full compatibility with all QForm features.

Integration allows you to:

use different forms on one page;
see in the CRM which variant generated the lead;
launch automatic actions (e.g., sending a proposal);
collect and filter data by segment;
get test analytics without manual work.

Now that we’ve covered how the script works and its capabilities, let’s sum up its benefits.

Why It's Convenient and Effective

Running tests with the QForm script is much simpler and faster than traditional code-based solutions.

Test setup takes minimal time: one script + one variants file. Everything runs and updates without risking site stability.

You choose what to change: headlines, images, forms, buttons, videos. It’s all configured in the channel.json file—no developer required.

The script works with any site: Tilda, WordPress, Bitrix, custom CMS. Goals are instantly sent to Metrica, and segment data integrates into QForm forms and reports.

This enables marketers to work efficiently: come up with a hypothesis → launch it → see results → lock in the best version.

Security and SEO Impact

When replacing content, it’s important to understand how it affects SEO and site stability.

Site Security

The script runs client-side—nothing changes on the server or in source code.
It connects asynchronously (defer), so it doesn't block page loading.
Even if the channel.json file is temporarily unavailable, the site continues working without errors.

Impact on SEO

Search engines (Yandex, Google) only see the original content, not the replacements. This prevents duplication and preserves indexing.
All content variants are tested on the same page—no new URLs or duplicates. This helps maintain search rankings.
Adding QForm video widgets—also testable via this script—boosts behavioral metrics: time on site, engagement, depth of visit. These positively affect SEO.

The script has been tested on popular platforms and does not conflict with analytics, A/B testing systems, form builders, or third-party widgets.

Conclusion

The QForm content replacement script is a convenient and safe way to run A/B tests on your site. Setup is quick: just connect the script, create a JSON file with variants, and define which blocks to change. There’s no need to alter the site structure or modify the code.

Test results are immediately sent to Yandex.Metrica, and you can use the variants in lead forms and CRMs. This gives marketers full control: which version performed better, where conversions are higher, how users respond. Meanwhile, technical processes don’t affect SEO—search bots see stable source content, and replacements happen only for live users after page load.

QForm makes testing fast, flexible, and transparent. It’s a tool that lets you run experiments daily—not quarterly—and immediately see what works best.

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