I would like to build a location tagging website for personal/private use. I seek your assistance in buying a good offline GPS enabled device that helps me build data for my website.

Here is my plan:
I will browse my website using the device (like within wifi or localhost or even using 3g data card).
It will instantly trap the current latitude and longitude of my current position, and auto-fill-up the HTML form using javascript location service.
I will fill up the few other form fields like the name of business and location etc. to complete the website data.
Of course, I may snap and upload a picture as well.

I am not being able to find out a good device to help me with these requirements.
What hardware can help me? iPad? Nexus? Lumia? Camera with GPS? What?

If only one device can help me, it would be great. But which one?
This would make traveling easier to collect the location based data I want.