Topic: how can put script js on [full-link]

hi guys, im using shadowbox for text_box, and i wanna use in "read more" but dont know where put the code, this is my code <div class="fullink"><a rel="shadowbox"[full-link]Read more...[/full-link]</a></div> but work badly,  i guess need work here

return ''.$t.'';
but dont know how set correct code, im only need for popup on read more, sry for my bad english guy thx