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You can delete a test variation only if the campaign is “Not Started” state. But, you cannot delete variations from a running or paused test. Deleting variations from a running campaign will affect the statistical integrity of your website data because running tests would have started collecting data and removing a variation may corrupt your test reports or mislead your decision -making process.

As a best practice, we recommend that you first clone the test, delete the variation from the cloned test, and then start the campaign. To learn how to clone a test, click here.

To delete variations if the test is in the not started mode:

  1. Open the test you want to edit.
  2. Click the three vertical dots next to Start.
  3. To open the page in the VWO editor, select Modify in Editor.
  4. In the editor, go to the Variations section, and then click the Settings gear icon.
  5. In Variation 1 options, click Remove to delete the variation.

You can also disable a variation if you no longer need it for the test. Click here to learn how to disable a variation.

You may, at times, notice a page flicker. (See control for a split second before the variation loads). The following are some possible reasons for the page flicker:

  • The VWO smart code was added via a tag manager: When using a tag manager to load the VWO code, ensure that the tag manager is set to Synchronous code. When the tag manager is set to Asynchronous code, your visitors might see a flicker in the variations loaded. This means that when visitors are supposed to see a variation, they will see the control page for a moment before the changes appear, as the code is loaded by the tag manager. As a best practice, you should manually add the VWO smart code directly on your campaign pages. Reach out to VWO support for any assistance.
    For example, VWO supports integration with the Tealium tag manager flawlessly when Tealium settings are configured with Synchronous code.
  • JS code changes causing the page to flicker: If visitors use only the operations supported by visual editor, they know the exact elements modified and hide them until a variation change is loaded. But if you add a JavaScript code snippet to change some elements on the web page, you might notice a flicker—original content will flash before the change is applied—on the live site. To minimize the flicker, run the script as soon as its target element is ready on the page, as shown in the following code snippet.
    // Avoid multiple setIntervals gettings started.
    if (window.vwoElInterval) {
    window.vwoElInterval = setInterval(function() {
    if (vwo_$(CSS_SELECTOR_PATH_OF_ELEMENT).length) {
    // Make changes that require the element to be present

    Reach out to VWO support for any assistance.

  • The VWO smart code is added to the bottom of the webpage and not in the header: If the VWO smart code is added at the end of the web page, the browser executes the VWO code only in the end. In the meantime, you may notice a flash of the original (or control) page before you see the variation page. Ensure that the VWO code snippet is added to the header of the web page.
  • Change image operation: If you add large-sized images to the variation, the images may take some time to download on the page. Until the images are downloaded, old images/content continue to be displayed. This might appear like a page flicker to the visitors. Here is a workaround for this problem.

Yes, you can make changes to iframe tags in your website. Using VWO Editor, you can edit the iframe URL, change style and placement, and so on. To use the feature, you must first load the webpage containing the iframe content into Visual Editor. On clicking the element, the editor provides the following options to modify the iframe content.

No, you don’t need to make any extra effort to track conversions on HTTPS websites. You just need to use “https” in the goal URL while defining your test goals.

Make sure you use correct URLs while defining the goals. Use appropriate regular expressions and page patterns when running the campaign on multiple pages. Click here to read how to use URL patterns in VWO.


Ensure that loading mixed or secured content is enabled on your browser. Click here to enable blocked content on your website.

By default, VWO includes the query parameters appended to the URL. For example, if you specify the campaign URL as, then the campaign automatically runs on the URLs such as (Here, test1 and test2 are query parameters.)

However, if you have manually specified some query parameter under Included URLs, then the campaign runs on this URL only and no other query parameter is allowed. For example, the campaign will not run on the URLs of type

In case of a split URL test, the query parameters appended to the control URL are forwarded to the variation URL. For example, in a split URL test:

  • If a user lands on the URL, then the corresponding variation URL is
  • If the variation page already has some other parameters, you should add an asterisk (*) at the end of the control and variation URLs to handle the parameters.

Yes, multiple campaigns can be run simultaneously across a website funnel. Here are the two scenarios for this case:

  1. Running different campaigns on different steps of the funnel so that no two campaigns are running at the same time on the same page. This setup will run smoothly, because the settings will be loaded separately for different pages, not causing any mismatch. There are two ways to do it:
    • Use VWO cookies to set up a funnel test across multiple pages. To learn more about how to implement a change across your website funnel, click here.
    • Run a single campaign across all the pages by making changes to those pages while you go through them, using the campaign builder.
  2. Running multiple campaigns on the same page(s) at the same time. To run this setup, ensure that the changes made from within the campaign builder are not made to the same or overlapping elements. If the changes are made to the same element, then the campaigns may conflict with each other.

The following are some factors that affect the conversion rate of a website:

  • Elements modified: The elements you modify in a test page impact its conversion rate. Be sure to select elements that are most prominent in the test page. If you modify less significant elements such as footer, you may not notice much improvement in the conversion rate.
  • Difference in variations: You may notice a significant difference in conversions if variations are drastically different from the control version of the test pages. If changes in the variations are minor such as increasing the font size, the difference in the conversions rate could be minimal.
  • Number of variations: Larger the number of variations, higher the chances of coming up with a winner. However, having a large number of variations requires you to run the campaign for a longer duration.

Although improvements in conversion rates vary according to the type of a website, a conversion rate difference of >10% can be considered reliable. In some cases, you may even get more than 200% improvement in the conversion rate.

Yes, you can use VWO to set up changes in the AJAX elements on a webpage.

VWO applies changes to an element as soon as tracking code is loaded and doesn’t wait for the full page to be ready. In case you add an element later on the page through AJAX, use the following JS code snippet in VWO Code Editor:


_vis_opt_element_loaded(campaign_id); //change campaign_id as per the experiment ID


This is useful when changes are applied using editor operations.

If this does not work, you need to apply the changes through JavaScript code, using VWO Code Editor. While writing custom JS code, you should use vwo_$ (VWO’s inline jQuery handle) instead of $. This would ensure that JS code is executed when VWO code is triggered and is not dependent on the jQuery of the page.

You can also use the setInterval() function to check the target element; and when it’s available, apply the change, as shown in the following code:

if (window.timerX) clearInterval(window.timerX);

window.timerX = setInterval(function() {

if (vwo_$('E1').length) {

// script S1 here.


}, 100);

If your website is a single-page application, you need to execute the VWO tracking code, as explained in this article.

No, use of VWO does not have a negative impact on your website ranking. For A/B and Multivariate tests, both the control and variations run on the same URL and test changes are made by VWO on the fly. There is no scope for content duplication which otherwise can affect your SEO ranking.

Even though Google crawlers support JavaScript and the variation page of A/B test campaign can be crawled by Google bots, they do not affect the performance of the A/B website. Google also has its own A/B testing solution which would not exist if such tests affected rankings of the website.

However, SEO issues may crop up when you are running a Split URL test. To avoid the issue, use query parameter rel=”canonical” in the variation URL to avoid duplicating content. For example, in your Split URL test, there are two pages (say, and When visitors land on, half of them are redirected to that contains some duplicate content on it.

In such a scenario where you don’t want B.php to affect your SEO, avoid content duplication. To do so, add the following code to B.php, that is, the noncanonical page:


<link rel="canonical" href=""/>


While Google will index both the pages, by adding the above code, you are telling Google to use only for SEO purposes. Here’s the Google link on using canonical URLs

The following are best practices for creating and running tests on your website. You can refer to the original article from Google here.

  • Don’t cloak your test pages
  • Use rel=”canonical” links
  • Use 302 redirects, not 301 redirects
  • Run the experiment only as long as necessary

Absolutely yes. VWO requires only your root domain and works as long as the root domain is the same.

For example, you want to create a Split URL test for a website (which is your control version). The variation you create for the test is In this case, your test will work on both the domains because the root domain of both is the same, that is, 

ATTENTION You need not enable the Campaign involves multiple domains option while creating a test on sub-domains, as explained in the example above.

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