capture cards as in, a tv card for a computer, and capturing shows via tv, or cable or satellite? and/or a capture card you hook a camera up to?
you will be looking at flash, java, or html5 plugins. that deal with a video camera / camera for recording video. as long as the plugin allows you to select a camera, you should be able to select the capture card as well. (assuming you have correct drivers installed) your issue is more on the operating system and driver side for the capture card more than anything.
on microsoft window computers, you should be able to open a video recording software. and select between a usb camera and/or a capture card. if you can. then more likely any software will work. that can capture video.
capture card = taking cover off computer and install the capture card. vs connecting via usb port. not real big difference there. as long as you have correct drivers installed.