Buying need javascript which adds text to clipboard when text is copyed from my website

hi,

also i need a javascript script which adds text to the clipboard when someone copyes text from my site.

for example:

someone copyes this text from my site:

"text on my site"

and then when he pastes it somewhere, this should be pasted:

"text on my site - copyed from mysite.com"

 

I can do this

 

for how much?

EDIT: i can pay via paypal.