Track Viewer on Gmap

I don’t mind that I am the only user, but if someone else like it, I would be glad. That’s why I published this application.
Track Viewer on Gmap is used to view TRACKS of gpx files(and Google Spreadsheet). Saving selected tracks and optionally combine them into one single track is also possible.
Simple demostration:
Go to http://photo.vito.tw/track/.
You will see

look at the right top coner, below GMAP control:

All functions are listed as icons, and they are:
Load – load tracks
Save – save selected tracks to another GPX file.
Show/Hide Track Summary -show or hide information about selected track.
Show/Hide Altitude Chart – show or hide altitude chart of selected track
Show/Hide Speed Chart – show or hide speed chart of selected track
Show/Hide Track List – show or hide the “Track List”
About
Let’s start from “Load”. You can load track from data of Google Spreadsheet. Of course, the spreadsheet must be published and formated.

Or, you can open GPX file specified as URL, the url should be public accessible.

Or, you can upload an valid GPX format file as the third option. Note: since Javascript cannot access local file, the local gpx file must be uploaded and then downloaded, so it will take some time to finish loading.
Once tracks are successfuly loaded, you can find a list of tracks below the tool icons.
Check/uncheck the checkbox to show/hide the track.
Click the track name to SELECT the track.

You can hide the Track List.

Click the 3rd tool icon to show Track Summary.

Alitude/Speed charts. You can click on the chart, and the coresponding point on map will be shown.

You can save showing track into another GPX file. Showing tracks are those shown on map with checkbox checked. You can “combined” them to a single track with specified track name.