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new html extension proposal

From: <AChen@jgc.com>
Date: Mon, 21 Aug 95 09:28:32 PST
Message-Id: <9507218090.AA809024698@jgc.com>
To: www-talk@w3.org
     I would like to propose a new extension to HTML, the X-ALTSRC 
     attribute in the <IMG> tag. Currently, many of the major browser 
     companies, such as Netscape and America Online support this extension.
     Its general form is: <IMG X-ALTSRC="[mime/type;]URL"> When used in 
     conjunction with the SRC attribute, this new attribute allows users to 
     specify an alternate source file that can be used to display a graphic 
     Here's an example: 
     In this case, ABC-enabled browsers would read the entire IMG tag and 
     use /images/daytona.abc instead of /images/daytona.gif. Old-style 
     browsers, who know nothing of X-ALTSRC, would use /images/daytona.gif. 
     This format is called "dual encoding. 
     The optional [mime/type;] portion of the attribute lets a user 
     explicitly tell the browser the format of the file that follows, 
     rather than having the browser determine the format based on the file 
     extension, its default behavior. Here's a variation of the previous 
     example that illustrates how it works: 
     X-ALTSRC="image/x-abc;/images/daytona.v1" >
     In this case, the browser knows that the file format is ABC-based on 
     the mime/type, and the file extension is ignored.
     Feedback ... comments? What is the next step from here? Is there a 
     formal procedure to go through?
     Albert Chen
Received on Monday, 21 August 1995 12:42:02 UTC

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