'observe' on 'MutationObserver': parameter 1 is not of type 'Node'
I am creating a Chrome extension and trying to include a small text beside the SEND button of the gMail compose box. I am using a MutationObserver to know when the compose box window appears. I am doing this by observing an element with class no since the compose box element is created as child of this element (class no ). When the user clicks on the compose button and the compose box window appears, then I place an element beside the SEND button using the .after() method. SEND button class name is .gU.Up . These are the real class names of gMail and pretty weird too. Below is the code I am