How to active inbuilt PDF reader in Firefox 15

With Firefox 15, we know the most important new feature is Inbuilt PDF viewer. We could view pdf files without installing adobe plugins in Firefox 15. But the PDF reader is not enable in default.

Now we need to active the New PDF Reader.
1. Open your Mozilla Firefox 15.

2. Type "about:config" in the address bar and Click "Enter". 

3.Click on "I'll be careful, I Promise".

4. Type "PDF" in the search box and start search.

5.Find "pdfjs.disabled". Double click on "pdfjs.disabled" then you will get custom settings, "true" become "false".

At last, restart the Firefox, and have a try with a online pdf file.