Custom LightBox Jquery Error | remove

I have been using custom lightbox. So i added onclick events for buttons.

Close = lightbox.close() Save = Delete = lightbox.remove()
Of this only close works for rest of the buttons i get script error
TypeError: lightbox.remove is not a function

Included JS

More on this even when JS are included and lightbox.close() works on button but it does not work when it is fired from firebug even lightbox.close() throws the same error but works on button.

please show some more code, namely lightbox markup