Smallpox is a quick hack to emulate document.write and capture the output inside an arbitrary DOM node.

This allows asynchronous loading of legacy JavaScript code, as well as usage in XHTML documents, which do not support document.write.

Smallpox overrides the document.write method, gathering the output in a buffer and then appending it to the innerHTML property of the DOM node. Before that, the output is processed with a minimal parser to allow inclusion in an XHTML document.

Include the script and call the smallpox function as follows:

smallpox(id, url, done)

• id: The ID of the element to capture the output in.
• url: The URL of the script to include.
• done: An optional function to be called when the script has finished.

The following code shows how to use Google Adsense in an XHTML document:

<div id="ads">
	<script type="application/javascript" src="smallpox.min.js"></script>
	<script type="application/javascript">
		google_ad_client = "ca-pub-XXXXXXXXXXXXXXXX";
		google_ad_slot = "XXXXXXXXXX";
		google_ad_width = 160;
		google_ad_height = 600;

		smallpox('ads', 'http://pagead2.googlesyndication.com/pagead/show_ads.js');
	</script>
</div>

In this naïve example, loading the Smallpox script blocks the parser, but in a real‐world scenario it should be embedded directly or loaded asynchronously.