Help with AppleScript

Hey guys. I am new at using applescript. I found an applescript that lets me capture a current tab and email it.

The below is the applescript:

tell application "Safari"

tell front window

email contentsofcurrent tab

end tell

end tell

I would like to add to this applescript to a) automatically activate when someone clicks on an application and b) to have it automatically email the tab content to my email address, without anyone knowing that this occured.

Can anyone help me out here?

Thanks.