Page

bkhtmltopdf adheres to standard HTML/CSS specifications, allowing you to freely write HTML code to define page layouts. The core functionality is controlled via CSS @page rules to manage print output (such as page size and orientation). Below is a detailed guide with examples.

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Hi, bkhtmltopdf!</title>
</head>
<body>
<h1>Hello World!</h1>
</body>
</html>

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Size

bkhtmltopdf supports multiple standard page sizes. Specify them using CSS @media print and @page rules: Several standard page sizes are available:

Predefined Sizes

Below are common standard sizes (in mm):

Size	Width × Height	Description
A3	297 × 420	Large posters/charts
A4	210 × 297	Standard letterhead
A5	148 × 210	Books/booklets
B4	250 × 353	Japanese Standard
B5	176 × 250	Japanese Pamphlet
Letter	216 × 279	US Letter
Legal	216 × 356	US Legal Document
Ledger	432 × 279	US Ledger

Example: Setting A5 Size

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Hi, bkhtmltopdf!</title>
    <style>
        @media print {
            @page {
                size: A5;
            }
        }
    </style>
</head>
<body>
<h1>Hello World!</h1>
</body>
</html>

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Units

If predefined sizes don't meet your needs, you can manually specify width and height. Supported units include:

• mm
• cm
• in
• px (pixels, based on 72 DPI)

@media print {
    @page {
        size: 210mm 297mm; /* A4 */
    }
}

tip

Pixel units are suitable for screen adaptation but convert to physical units during printing. Use mm or cm for guaranteed precision.

Page Orientation (Landscape/Portrait)

The default orientation is portrait. To switch to landscape, add the landscape keyword within @page.

@media print {
    @page {
        size: A5 landscape;
    }
}

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Custom Orientation Notes

When using custom sizes not predefined, manually swap width and height:

@media print {
    @page {
        size: 210mm 297mm; /* A4 portrait */
        /* size: 297mm 210mm; /* A4 landscape (commented example) */
    }
}

JavaScript

bkhtmltopdf fully supports JavaScript, including inline scripts and externally loaded scripts. JS is executed during rendering to dynamically generate content. You can use script tags or include external script files.

<!doctype html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Hi, bkhtmltopdf!</title>
    <script src="https://cdn.jsdelivr.net/gh/jquery/jquery/dist/jquery.min.js"></script>
</head>
<body>
<h1>Hello World!</h1>
<p id="dynamic">Loading...</p>
<script>
    document.getElementById('dynamic').innerHTML = 'Hello from JavaScript!';
</script>
</body>
</html>

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tip

JS execution timing is influenced by the waitUntil parameter. For complex interactions, use waitUntil: manual to ensure full rendering.