Cross-origin iframes

DevBridge supports reading and interacting with content inside cross-origin iframes — including Out-of-Process iframes (OOPIF).

Supported tools

The following tools operate across all frames including cross-origin:

• read_page — accessibility tree includes all frame content
• find — searches across all frames
• form_input — can fill inputs inside iframes
• computer (click, hover) — can interact with elements inside iframes
• file_upload — works inside iframe file inputs
• javascript_exec — can execute in a specific frame

Element references

Elements inside iframes use a three-part reference format:

f{frameId}::s{hostBackendId}::ref_N

For example: f2::ref_5 refers to element ref_5 in frame 2.

When you get an accessibility tree via read_page, frame elements are automatically prefixed so your AI tool can reference them precisely.

Fallback for OOPIFs

For true cross-origin Out-of-Process iframes, DevBridge uses chrome.scripting injection as a fallback, ensuring compatibility even when CDP cannot directly access the frame.