Data URLs allow small document data to be included in the URL itself. This is useful for very small HTML testcases or other occasions that do not justify a document of their own.
(note the comma after the colon) will deliver a text document that contains
The last example delivered a text document. For HTML documents one
has to specify the MIME type
is a testcase</p>”. This will produce exactly the same
output as if the content had been loaded from a document of its own.
Specifying alternate character sets is also possible. Note that 8-Bit
characters have to be escaped by a percentage sign and their two-digit
data:;charset=iso-8859-1,Gr%FC%DFe aus Schl%E4gl”
Grüße aus Schlägl”
whereas omitting the charset attribute might lead to something like
Gr??e aus Schl?gl”.
IETF RFC2397 provides more information.