Issue: Ad Calls Prevented When document.body Isn’t Ready

[lksharma]

Description
In version 9.4 and later, a change was introduced that prevents ad calls from being made if document.body isn’t ready. This issue is linked to the changes made in this commit, which added a location method for cross-frame creatives.

Affected Version: 9.4+
Introduced in: PR #11863
Test Page: https://30f9d51a.demo-ann.pages.dev/testpage

Steps to Reproduce

1. Visit the Test Page: Open the test page provided.
2. Check the Console: Observe the console for errors related to appendChild caused by adRendering.js#L258
3. verify no ad calls are made for configured bidder (ex: /openrtb/pbjs)

Expected Behavior
Ad calls should be made regardless of whether document.body is fully loaded or not and no Uncaught error should be thrown by pbjs

Actual Behavior
When document.body isn’t ready, the following error is thrown, preventing ad calls from going out:

TypeError: Cannot read properties of null (reading 'appendChild')
    at insertLocatorFrame (adRendering.js:258:19)
    at pbjsInstance.processQueue (prebid.js:979:21)

Analysis

• The error originates from the insertLocatorFrame function in adRendering.js#L258.
• The issue arises when pbjs is loaded synchronously or when document.body isn’t available at the time of appendChild call.
• This problem does not occur when pbjs is loaded asynchronously because the script execution is deferred until document.body is available.

Proposed Solution
Ensure that document.body is ready before attempting to call appendChild. A potential solution is to check for the existence of document.body before executing insertLocatorFrame.

export function insertLocatorFrame() {
  if (!window.frames[PB_LOCATOR]) {
    const frame = createInvisibleIframe();
    frame.name = PB_LOCATOR;
    if (document.body) {
      document.body.appendChild(frame);
    }
  }
}

[olafbuitelaar]

this should solve it; #11926

[lksharma]

Thank you

[patmmccann]

Thank you!

[patmmccann]

Do we think this warrants a patch release to 9.4?

[lksharma]

A patch release for version 9.4 makes sense to me since it affects the ability of ad calls to go through.