If someone know that there is any tools having these function below, please recommend it to me.
(Extract email address from online website,test article and search engines and a better price)

thanks

From a single page? or a web site?

I hope searching the page of the whole website

For a single page you can drag and drop the URL form your browser to eMail Extractor. You can drop as many page as you need one after the other and save e-mail addresses to the same list.

For a site you have to use Web Dumper and activate the e-mail extraction feature from the preferences.