How could I link the items in the table of contents to their respective target pages?

I am currently using the XHTML2PDF library to turn html t开发者_如何学Pythono PDF file,and generate the table of contents with page number behind based on some html tag such as H1, H2, this is really nice feature.

But my problem is the generated table of contents are static items, how could I turn them into clickable ones, when i click on it, I want it to take me to the target page.