Gmail now allows user to open and view PDF in browser. No additional plug-in is required.
These feature is pretty convenience when you open a PDF file from your friend on a public computer (e.g. Cyber cafe) which is no acrobat reader is installed. When you receive a PDF file in your Gmail inbox, simply click “View” will quickly opens the PDF inside your browser, complete with the graphics and formatting you expect to see in a PDF.
Besides viewing the PDF file online, you still can view it in HTML format or download and save it on your computer for offline viewing.