I am writing a chrome extension. I am wondering if there is a way to make the popup window transparent, that is the user can see the content of the current page even the popup w
There doesn't seem to be a way to do this. Chrome defaults to a popup background of white, unless you change it within your extension.
Google does mention that the popup will resize to its content, however. http://developer.chrome.com/dev/extensions/browserAction.html#popups
An interesting idea came to me mind yesterday, though you can't remove the white background, you can still mimic a transparent background.
This will be done by taking a screenshot of the page right before opening the popup and place it as a background image of the popup. I'm not sure how the background-image position calculations will go and if even possible but go give it a try.
Of course you will still have the popup's white border and box-shadow, but it should still look quite good.
Notice that this trick may not work good if there is any movement behind the popup as:
Taking a screenshot is done using captureVisibleTab
from a background-script:
https://developer.chrome.com/extensions/tabs#method-captureVisibleTab
You will use messages or storage to send the screenshot image data to the popup.