If you have both opened with sized windows you could potentially have excel using 1/2 the screen and the web browser using the other half. Transfer from one to the other you can manually copy/paste info across unless the content is protected from copy/paste or an image form where numbers are actually an image vs ascii.
Anything like this for large amounts of data, you either would program a keyboard/mouse macro to run through redundant process such as using jitbit Macro recorder or another macro creation software or you can write a C# program for example that parses a website for information and passes that information such as comma delimited to a CSV file to be opened in excel later as a raw data import.