gwtar_noscript.html

Path: build/gwtar_noscript.html | Language: HTML | Lines: ~13

Fallback content displayed when a .gwtar.html file cannot be loaded normally.

Overview

gwtar_noscript.html provides the error messaging UI for the gwtar self-extracting archive format. It's embedded within <noscript> tags in every .gwtar.html file and displays contextual help when:

JavaScript is disabled in the browser
The file is opened locally (via file:// protocol)
The server fails to serve the file correctly

The content is intentionally minimal—just text and basic styling—since it must work without any external assets or JavaScript.

Content Structure

Main Message

<p>This HTML page <span class="js-disabled-warning">
<strong>requires JavaScript to be enabled</strong> to render, as it
</span>is a self-extracting <code>gwtar</code> HTML file.</p>

Explains the gwtar format with a link to documentation.

Local File Warning

<div class="local-file-warning" style="display: none;">
    <p>You are seeing this message... because <code>gwtar</code> files
    <strong>cannot be opened locally</strong>...</p>
    <p><code>perl -ne'print $_ if $x; $x=1 if /&lt;!-- GWTAR END/'
        &lt; <span class="gwtar-file-base-name">foo</span>.gwtar.html
        | tar --extract</code></p>
</div>

Provides a shell command to manually extract the tarball when opened as a local file.

Server Failure Warning

<div class="server-fail-warning" style="display: none;">
    <p>...the web server is incorrectly configured or does not support
    <code>gwtar</code> files...</p>
</div>

Indicates a server-side configuration problem.

How It Works

Display Logic

The content sits inside <noscript> tags, so browsers show it when JavaScript is disabled. When JavaScript IS enabled, gwtar.js handles display:

// In gwtar.js handlePageRequestFailure():
let noscript = document.querySelector("noscript");
noscript.outerHTML = noscript.innerHTML;  // Unwrap noscript

// Hide all warnings first
document.querySelectorAll(warningsSelector).forEach(warning => {
    warning.style.display = "none";
});

// Show appropriate warning based on protocol
if (location.protocol == "file:") {
    document.querySelector(".local-file-warning").style.display = "";
} else {
    document.querySelector(".server-fail-warning").style.display = "";
}

Dynamic Content

The script populates placeholder spans:

.gwtar-file-base-name - Gets the actual gwtar filename
.html-file-base-name - Gets the extracted HTML filename

CSS Classes

Class	Purpose
`.js-disabled-warning`	Text shown only when JS is disabled
`.local-file-warning`	Container for local file instructions
`.server-fail-warning`	Container for server error message
`.gwtar-file-base-name`	Placeholder for gwtar filename
`.html-file-base-name`	Placeholder for HTML filename

Manual Extraction Command

The provided shell command extracts the tarball portion:

perl -ne'print $_ if $x; $x=1 if /<!-- GWTAR END/' < foo.gwtar.html | tar --extract

How it works:

Perl reads the file line by line
Starts printing after the <!-- GWTAR END marker
Pipes the tarball data to tar --extract
Results in the original HTML and all assets

Integration

Embedded in gwtar Files

This HTML is concatenated into every .gwtar.html file during the build process, wrapped in <noscript> tags.

With gwtar.js

The JavaScript loader (gwtar.js) manipulates this content's visibility based on the detected failure mode.

Overview​

Content Structure​

Main Message​

Local File Warning​

Server Failure Warning​

How It Works​

Display Logic​

Dynamic Content​

CSS Classes​

Manual Extraction Command​

Integration​

Embedded in gwtar Files​

With gwtar.js​

See Also​