Are 'empty' heading tags acceptable for generating a table of contents?

Derek R · 05-20-2014, 10:19 AM

I usually generate the table of contents from <h1> tags. However, there are occasions when I don't want headings displaying at the top of particular sections in an ebook. For instance, I would want to avoid having a heading appear above the frontispiece in the xhtml file that I have created for that image. Rather than have <h1>FRONTISPIECE</h1>, for example, is it acceptable to simply have <h1></h1> with nothing between the container tags and then edit the toc to include 'Frontispiece' as the section title? Or is it bad practice to use tags in this way and, if so, what is the best alternative?

Jellby · 05-20-2014, 11:12 AM

You don't need a heading tag for a TOC entry, it's enough with an "id" in any element, for instance:

Code:

<p class="dedication" id="ded">To my mother</p>

and then just use "...#ded" in the "src" attribute (I think that's the correct one) in the TOC file.

It's only automated tools which "need" heading tags to build the TOC for you, but if you are going to edit it anyway, you are not constrained by the tool's options.

EDIT: Or, more simple yet, if you want the TOC entry to point to the top of a file, you don't need the "id" at all.

Derek R · 05-20-2014, 11:58 AM

Thank you, Jellby. I stupidly forgot to mention that I am generating the table of contents in Sigil. However, your response clarified my thinking. I can generate the TOC initially with the h1 tags and then by using 'Edit Table Of Contents' I can add further items.

RbnJrg · 05-20-2014, 02:58 PM

Quote:

Originally Posted by Derek R

I usually generate the table of contents from <h1> tags. However, there are occasions when I don't want headings displaying at the top of particular sections in an ebook. For instance, I would want to avoid having a heading appear above the frontispiece in the xhtml file that I have created for that image. Rather than have <h1>FRONTISPIECE</h1>, for example, is it acceptable to simply have <h1></h1> with nothing between the container tags and then edit the toc to include 'Frontispiece' as the section title? Or is it bad practice to use tags in this way and, if so, what is the best alternative?

Well, if you are working with Sigil then is a piece of cake what you want

Just use (in the place you want):

Code:

<h1 title="FRONTISPIECE"></h1>

and after pressing Ctrl+T, you'll have a TOC entry with the name FRONTISPIECE.

So, what you need to do is to write with the global attribute "title" what you want to appear in the TOC. Examples:

Code:

<h1 title="This is a TOC entry"></h1>
<h2 title="Another TOC entry"></h2>

and so on

Of course, tags <h1..h6> can be empty.

Regards
Rubén

Derek R · 05-20-2014, 03:29 PM

Thank you, Rubén - I've tested that and it works a treat - a handy tip indeed.

eschwartz · 05-21-2014, 12:22 AM

Wouldn't conversion be likely to delete these empty tags? Probably not a big deal, but I use

Code:

<h1 class="hidden">This is a ToC entry</h1>

with css of

Code:

hidden {display:none}

Derek R · 05-21-2014, 02:12 AM

Another excellent tip - thank you, eschwartz. That css was not in my armoury until now. It led me to discover that the following could also be used:

Code:

Code:

<h1 class="hidden">This is a ToC entry</h1>

css:

Code:

.hidden {visibility:hidden;}

which will hide the text between the tags but take up the space of the <h1> element.

Jellby · 05-21-2014, 03:24 AM

Quote:

Originally Posted by Derek R

Code:

.hidden {visibility:hidden;}

which will hide the text between the tags but take up the space of the <h1> element.

But "visibility" is not among the CSS properties required for ePub 2.0.1, so don't be surprised if it is not supported by some reader.

Derek R · 05-21-2014, 03:34 AM

Okay - thanks - then sticking to "display: none" seems to be the safer bet, although on devices where "visibility" isn't supported presumably the content of the container tags would display, which wouldn't be entirely disastrous.

RbnJrg · 05-21-2014, 07:54 AM

Quote:

Originally Posted by eschwartz

Wouldn't conversion be likely to delete these empty tags?

I don't think that but even so, the TOC will remain unchanged. You can be sure that the attribute "title" will be serviceable to generate a TOC.

mrmikel · 05-21-2014, 10:13 AM

On some readers, hidden text will hide the text alright, but if it is in the middle of a line, it will leave a blank space and cause text to be shoved over to the right edge. I try to avoid this for my old PRS-300.

eschwartz · 05-21-2014, 10:18 AM

Quote:

Originally Posted by RbnJrg

I don't think that but even so, the TOC will remain unchanged. You can be sure that the attribute "title" will be serviceable to generate a TOC.

I think I remember discussion about empty paragraph tags used for scene breaks instead of css margins being inadvisabe for this reason. I would try to avoid breaking things down the line... someone else might be inconvenienced later on.

Anyway, this does work, and I can't think of a downside, even a potential one. Momentum alone should keep me using it.

Abekonge · 05-23-2014, 05:34 AM

I always use <h1 style="display:none">Toc-entry title</h1> - works like a charm.

05-20-2014, 10:19 AM	#1
Derek R Zealot Posts: 104 Karma: 20 Join Date: Jun 2011 Location: County Down, Northern Ireland Device: none	Are 'empty' heading tags acceptable for generating a table of contents? I usually generate the table of contents from <h1> tags. However, there are occasions when I don't want headings displaying at the top of particular sections in an ebook. For instance, I would want to avoid having a heading appear above the frontispiece in the xhtml file that I have created for that image. Rather than have <h1>FRONTISPIECE</h1>, for example, is it acceptable to simply have <h1></h1> with nothing between the container tags and then edit the toc to include 'Frontispiece' as the section title? Or is it bad practice to use tags in this way and, if so, what is the best alternative?

05-20-2014, 11:12 AM	#2
Jellby frumious Bandersnatch Posts: 7,515 Karma: 18512745 Join Date: Jan 2008 Location: Spaniard in Sweden Device: Cybook Orizon, Kobo Aura	You don't need a heading tag for a TOC entry, it's enough with an "id" in any element, for instance: Code: <p class="dedication" id="ded">To my mother</p> and then just use "...#ded" in the "src" attribute (I think that's the correct one) in the TOC file. It's only automated tools which "need" heading tags to build the TOC for you, but if you are going to edit it anyway, you are not constrained by the tool's options. EDIT: Or, more simple yet, if you want the TOC entry to point to the top of a file, you don't need the "id" at all.

05-21-2014, 12:22 AM	#6
eschwartz Ex-Helpdesk Junkie Posts: 19,422 Karma: 85397180 Join Date: Nov 2012 Location: The Beaten Path, USA, Roundworld, This Side of Infinity Device: Kindle Touch fw5.3.7 (Wifi only)	Wouldn't conversion be likely to delete these empty tags? Probably not a big deal, but I use Code: <h1 class="hidden">This is a ToC entry</h1> with css of Code: hidden {display:none}

05-21-2014, 02:12 AM	#7
Derek R Zealot Posts: 104 Karma: 20 Join Date: Jun 2011 Location: County Down, Northern Ireland Device: none	Another excellent tip - thank you, eschwartz. That css was not in my armoury until now. It led me to discover that the following could also be used: Code: Code: <h1 class="hidden">This is a ToC entry</h1> css: Code: .hidden {visibility:hidden;} which will hide the text between the tags but take up the space of the <h1> element.

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05-20-2014, 11:58 AM	#3
Derek R Zealot Posts: 104 Karma: 20 Join Date: Jun 2011 Location: County Down, Northern Ireland Device: none	Thank you, Jellby. I stupidly forgot to mention that I am generating the table of contents in Sigil. However, your response clarified my thinking. I can generate the TOC initially with the h1 tags and then by using 'Edit Table Of Contents' I can add further items.

05-20-2014, 03:29 PM	#5
Derek R Zealot Posts: 104 Karma: 20 Join Date: Jun 2011 Location: County Down, Northern Ireland Device: none	Thank you, Rubén - I've tested that and it works a treat - a handy tip indeed.

05-21-2014, 03:34 AM	#9
Derek R Zealot Posts: 104 Karma: 20 Join Date: Jun 2011 Location: County Down, Northern Ireland Device: none	Okay - thanks - then sticking to "display: none" seems to be the safer bet, although on devices where "visibility" isn't supported presumably the content of the container tags would display, which wouldn't be entirely disastrous.

05-21-2014, 10:13 AM	#11
mrmikel Color me gone Posts: 2,089 Karma: 1445295 Join Date: Apr 2008 Location: Central Oregon Coast Device: PRS-300	On some readers, hidden text will hide the text alright, but if it is in the middle of a line, it will leave a blank space and cause text to be shoved over to the right edge. I try to avoid this for my old PRS-300.

05-23-2014, 05:34 AM	#13
Abekonge Scripler Project Lead Posts: 19 Karma: 19304 Join Date: May 2014 Location: Copenhagen, Denmark. Device: Gameboy Color	I always use <h1 style="display:none">Toc-entry title</h1> - works like a charm.