javascript in epub

[KevinH]

Originally Posted by Quoth

A nonsense personal attack that ignores reality. If you need javascript then maybe you need to write an iOS or Andriod app.

In what way is this personal?

Look at all of your posts on MR in threads on epub3 and/or javascript objectively like a data analyst would. You have put down epub3 and javascript in every one of them! You do so in an authoritative voice quoting your "long experience". Your bias is showing.

I started programming in 1976 and was a paid professional programmer for a time in the late 1970s and early 1980s before I decided to go back and get a PhD in Operations/Applied Mathematics. But that in no way means my opinion is worth more than anyone else's so I try to clearly state an "opinion" and not a fact most of the time. But you are so wrong on these subjects. You do not need an application for simple javascript in an epub. And not all books are basic fiction. So intelligent use of javascript in epub can be useful. These are not debatable points.

Go back and re-read what you wrote. It is time to stop trying to close down epub3 and javascript threads on MR. You are not helping anyone. I will now put you on ignore. Please do the same for me. As we must agree to disagree.

And be forewarned that inside the Sigil area, where I moderate, your constant attacks on epub3 and javascript will not be tolerated.

[Slevin#7]

I agree that for most pure fiction stories EPUB2 is sufficient. But there are many other scopes where full EPUB3 functionality inlcluding JS would have great benefit. For example educational books with Q&A sections, interactive storylines, escape stories, science texts, etc etc.

Also, as soon as there is a broad support I would bet that there will be a more and more amount of some interactive content, and who can say today what some intelligent people might come up with. New technology usually brings new possibilities no one thought before of. So let's embrace the future together and make sure to always have enough coffee and cookies in handy...

[Quoth]

Originally Posted by Slevin#7

IFor example educational books with Q&A sections, interactive storylines, escape stories, science texts, etc etc.

An app is easier and more likely to work and easier to distribute for those. Once you have used the framework once different content is easy to swap for titles of the same functionality.

Science texts can certainly be done with zero javascript but benefit from epub3 reflowable as a more flexible alternate to PDF. PDF is better for fixed layout.

[RbnJrg]

Originally Posted by Slevin#7

I agree that for most pure fiction stories EPUB2 is sufficient. But there are many other scopes where full EPUB3 functionality inlcluding JS would have great benefit

Yes, it is true that if the design is not very demanding, CSS2 may be sufficient in many cases, but epubs should still be epub3 (even if they only use CSS2). If the device accepts CSS3 and you're only providing CSS2, then the users are receiving a reading experience inferior to what they can expect.

That's why all epubs should be epub3 (since they can be opened by devices that only support epub2), containing the best code available for modern devices and fallback code for older ones. This way, users with modern e-readers will get the best out of them, and users with older e-readers will still get a satisfactory, but not optimal, reading experience.

And even novels and fiction books, without demanding design, can benefit from JavaScript. How? In many of my comments, I've affirmed the convenience of having the following property declared in the stylesheet:

body {
font-size: 1em;
}

With this, all the dimensions of the other elements set to "em" are referenced to that size defined in body. So if at any point, in body, instead of "font-size: 1em" we have "font-size: 0.8em", ALL the elements of the epub set to "em" will reduce their size (it would happen the other way around if the font-size increases). And where does JavaScript intervene? Well, it's very easy with JavaScript to determine the height and width of the viewport, know the available space (we'll know if the epub was opened on a large, medium, or small screen), and thus set an appropriate font size. This way, if the script detects a large screen, it does nothing, but if it detects a small screen, it overwrites the font-size value for body in the stylesheet to, for example, 0.8em. And with just this, all the values set to "em" in the epub are reduced. Of course, this don't negate the users' ability to set the font size they prefer, but it does provide a starting point, a point of comparison, to see how the epub looks with the optimal font size based on the detected screen size.

There are also other uses of JavaScript for fiction epubs that greatly improve the layout (for example, preventing text from overflowing in a block regardless of the user-defined font size; the text will always remain adjusted to the block size). And of course, adding hyphenation on devices that don't natively support this feature. This topic was recently discussed on the Sigil forum, when I asked Kevin if he could enable the Fetch API so that the Hyphenopoly script could also work in Sigil.