Use scrollHeight instead of offsetHeight

[itsPG]

The original script seems not to work for my website.

After I traced the source code, I found that the offsetHeight may be replaced with scrollHeight and it works for me now.

[cferdinandi]

I'm glad this fixed the bug for you. This is the first time I've seen it reported though, and I'd like to better understand scrollHeight caused an issue for you—and why offsetHeight is therefore a better choice— before accepting this pull request.

[itsPG]

In my opinion, offsetHeight means how much pixel you can see in your browser, while scrollHeight means how much pixel you can scroll. You may simplely check the change of offsetHeight by toggling the console in Chrome. However, I have no idea why sometime offsetHeight changes but sometimes not.

http://i.imgur.com/iZ5jGXx.png
http://i.imgur.com/uCWcZS6.png

The offsetHeight will change if I adjust the size of console.

[cferdinandi]

I'm going to hold off on merging this until I can get more clarity on why one approach is preferable over another. Thanks.

[itsPG]

Thanks. Hope you can find out the answer for us.

[cferdinandi]

Another user has reported a similar bug, and your pull request seems to solve the problem. I'll be merging shortly. Thanks!