it's a little bit techie... but you can 'scroll' through some of the registers. Dont know if it works for all of them, but it works for the parishes I was searching that had images added.
What you do is add or subtract 1 from the image number in the URL (the web address in your browser).
e.g. to scroll through marriages for Clontarf, Dublin (Church of Ireland), start at
this link ...../reels/d-833-1-1-051.pdf
the image number is the 051 at the end of the address. To move to the next page change the image number in the webpage address to 052 and hit enter.
There are separate volumes for births and marriages, and the numbers are not always continuous and restart at new values when a new register volume is started. Once you find the a starting point you can try working forwards or backwards by altering the number.
The index system and searches are quite good, but if you are trying to double check a particular date, you could start off by locating an unrelated baptism or marriage in the right parish, in the relevant month and then scroll back or forward from there.
Each image shows one or two complete pages of the register.
Shane