Dmitry, can you please take a look? 

This was fixed in M66, I believe. Sorry for inconvenience! You can pass 1.2 meanwhile, and things should mostly work.

Thanks, I updated Chrome to 66, the popup message doesn't show now, either with 1.2 or 1.3.

But when I call Page.getFrameTree and Page.captureScreenshot, they both return 'undefined', here are my code：

chrome.debugger.sendCommand({tabId: tab_id}, 'Page.enable');
var frameTree = chrome.debugger.sendCommand({tabId: tab_id}, 'Page.getFrameTree');
console.log('frameTree: ', frameTree);
var screenShot = chrome.debugger.sendCommand({tabId: tab_id}, 'Page.captureScreenshot');
console.log('screenShot: ', screenShot);

Any suggestion on it?

You have to provide a callback to get result value. Please refer to https://developer.chrome.com/extensions/debugger for documentation.

@dgozman, I can get frameTree from callback API now, for each frame, I can see properties, like id, url, parentId, loaderId, etc, can I use them to get document of each frame? then search elements?

I'm working on a chrome extension, trying to get elements from web page, with pure javascript, I found window.frames cannot include dynamic-loaded frame.

With getFrameTree interface of dev-tool, I can get the basic info of dynamic-loaded frame now, the next step is get elements from this frame.

@dgozman, I can get document by DOM.getDocument interface now, and I can locate the element on the dynamic-frame by DOM.querySelector, the response is a nodeID, How can I get rect of this element(by a nodeID or a Node object from dev-tool)? like the function in javascript: getBoundingClientRect();