onclick go to url
<input type=button onClick="opener.location='https://www.plus2net.com/'" value='Make the Main window change'>
<input type=button onClick="opener.location='https://www.plus2net.com/html_tutorial/button-linking.php'" value='Bring the button linking tutorial again'>
<input type=button onClick="location='https://www.plus2net.com/'" value='Make the current window change'>
<input type=button onClick="self.close();" value="Close this window">