While on Windows Operating System, the use of the following key combinations help in typing the corresponding accented letters on any application, including the browser.
Windows Alt Codes:
Note: The numbers have to be pressed in quick succession and using the "NUM" keypad while holding the "ALT" key. This does no work with the number keys above the regular letters on the keyboard.
A very useful Glossary courtesy: Penn State University
Many more such shortcuts found at this page.
Image courtesy: http://www.creativepro.com/