Embedding .pdf inside .swf

This is quick, easy, to the point and doesn't require any third-party script:

<embed src="http://example.com/the.pdf" width="500" height="375" 
 type="application/pdf">

UPDATE (2/3/2021)

Adobe now offers it's own PDF Embed API.

https://www.adobe.io/apis/documentcloud/dcsdk/pdf-embed.html

UPDATE (1/2018):

The Chrome browser on Android no longer supports PDF embeds. You can get around this by using the Google Drive PDF viewer

<embed src="https://drive.google.com/viewerng/
viewer?embedded=true&url=http://example.com/the.pdf" width="500" height="375">

The standard Media Type (formerly known as MIME types) is application/pdf. The assignment is defined in RFC 3778, The application/pdf Media Type, referenced from the Media Types registry.

Media Types are controlled by a standards body, The Internet Assigned Numbers Authority (IANA). This is the same organization that manages the root name servers and the IP address space.

The use of x-pdf predates the standardization of the Media Type for PDF. Media Types in the x- namespace are considered experimental, just as those in the vnd. namespace are considered vendor-specific. x-pdf might be used for compatibility with old software.