How can I count CSS page breaks for printed HTML?

I am generating reports using HTML and I am using CSS to control the page breaking using page-break-after, etc. I have given the user the option to print multiple reports at once, which I create as sections of a single dynamically generated HTML document. Making it a single document allows it to be a single print job to avoid print spooling issues.

My problem is this: I would like to number the pages of a section of the larger dynamic HTML in the format "page x of n". However, if I let the printer do it, it sees the document (rightly) as a single document and numbers the whole document.

Is there any way I could determine when the CSS page breaks are going to occur, so I could count them for a section before printing, and put my own numbering (HTML element for example) in for the sections in the long single document?

It seems like there should be a way for me to do this, but over the past few days the solution eludes me, so I thought I would ping Stackoverflow.

UPDATE: What I ended up doing:

I have accepted Christopher's answer because although I didn't use it exactly, it pointed me in the right direction.

I ended up doing calculations on the content using jQuery, based on the paper size being printed to, margins, font size, etc. and then adding elements for page breaks that have CSS for page breaking. I track how many of the page break divs are added, and then update the html "page x of n" information in each page break div once all the content is processed. That allowed me to avoid having to know how many pages there would be at the beginning (thanks jQuery .each).

Obviously there are some issues with this solution:

1. The "page x of n" elements don't appear as true footers, but rather at t开发者_如何学编程he bottom of the content on each page. In my situation that is an acceptable compromise.

2. Splitting content elements that were in themselves larger than a page, especially considering most of the content is generated by php, got a little complicated. I made it work, but again, it requires assumptions that could break with printing variations.

3. The calculations depend on assumptions about the printed paper size, margins, font size, etc. In my situation running on an intranet, that is again an acceptable compromise because I can control those options. Additional code can be added to handle some amount of variation in future (paper size for example).

This solution, although not perfect and a little "brittle", solves my problem, allows me to print multiple reports at once avoiding printer spooling timeouts, keeps track of and restarts page numbering, and avoids generating PDFs as an intermediate step for printing.

I found this a oddly hard nut to crack, so I would still appreciate opinions and input on the solution.

Thanks!

UPDATE 2: Final solution... avoid the headaches yourself:

Although I went perhaps farther than I should have with this approach, with some small successes, in the end the solution really wasn't one because it just ended up being far too "brittle" to changes. Any change in report format, new content added to existing reports, paper size etc. broke the calculations and just ended up in a ridiculous amount of extra work!

So, the end solution? "Resistance is futile!" Just do the reports as PDFs. You may commence the "we told you so" chorus if you wish, I can take it ;-)

I went with the TCPDF library, which has been excellent, if a little tough going to get started. The examples are very helpful. Now I have complete customization over the report, and everything get generated as it should. Mulitple reports are easily created as a single PDF (preventing the print spooling issue) with page groups that allows for the numbering to work exactly as I need.

So, if you are trying to do something like this, I would recommend you cut to the chase, skip the frustration with HTML/CSS type reports, and do PDFs.

This will display page numbers, but not the total number of pages:

footer {
    position:fixed;
    bottom:0;
    left:0;
}

body {
    counter-reset: page_number;
}

#page-number:after {
    counter-increment: page_number;
    content: "Page " counter(page_number);
}

Having something like

<p id='page-number'></p>

in the footer.

Browser: Firefox 19.0.2

Ive been able to implement page breaks whilst creating PDFs for print, using wkhtmltopdf. though im not sure if my solution is compatible with non webkit browsers but im sure you can get a vendor prefix for all the broswers if needs be.

Heres what i did, using page-break-inside: avoid; & page-break-after: always;

Then using jquery I worked out the heights of my sections and calculated (if the page size is going to be a4) how many times a break occured, and numbered the pages dynamically using jquery and pdf footers (before creating the pdf) so when the user downloaded the pdf it was numbered correctly.

What I reccomend is setting the page up (as the print stylesheet) so that page numbers are visible at these heights in the page, using absolute positionsing perhaps.

but I dont think this is failsafe.

Give them a PDF to print, then you have more control and dont have to worry about the web-print stylesheet, provided the PDF download link is prominently dispalyed.

I'm assuming you place a CSS page break at the end of each report and not manually at the end of each page. So your problem is to know when a page break will occur naturally within a long HTML document. The answer is - you can't. Even if you know how many lines of a table fit on a page (for example) you'll only know that for a given page size and print settings. If somebody decides to print your report on legal paper scaled 200% then your document will never know that. In my opinion, your options are 1) guess or 2) don't worry about it.

You can't count page breaks, but you can count column breaks, which behave very similarly.

Wherever you have page break styles, pair them with a matching column break:

-webkit-column-break-inside: avoid;
-webkit-break-inside: avoid;

Then set the report to use columns that match the size of a printed page:

.page.precalc {
    width: 16800mm;
    height: 257mm;
    -webkit-column-width: 168mm;
    .content {
        width: 168mm;
    }
}

Column breaks work very similarly to page breaks, so you can determine the page number of an element simply by measuring the horizontal position.

var left = el.getBoundingClientRect().left;
pageNumber = Math.round(left/635) + 1

CSS columns still have somewhat spotty support, so may not print correctly. However, you can remove the .precalc style as soon as you are done with layout calculations, so that the view will return to the original vertical layout. Depending on use case, a screen/print media query could also work.

The above works for me to generate a table of contents with phantomjs. Getting it to work in an arbitrary browser controlled by the user is somewhat more complex.

The following snippet will produce; a print page break before each h2 on the page.

extracted from here

<style type="text/css">
  h2 {
    page-break-before: always;
  }
</style>