Occasionally, Internet Explorer determines the plug-in type; however, Internet Explorer still displays the broken plug-in icon instead of the document.
The only information that is needed in return from the contype request is the content-type. However, because most developers are unaware of this request style, they treat each GET the same and return the entire document. This is where the second problem can manifest itself. Internet Explorer is hard coded to time out in only 10 seconds if the contype request is not answered. If you are reading large files from disk or opening a database to retrieve the file, you can easily exceed the 10 second time-out limit.
In Internet Explorer 4.x and 5, the browser first generates a GET request to the server. The server responds with the content-type, and the browser looks at the registry to check which application it will invoke. Then the browser generates a second GET request, and, after the server responds with the same content-type, the browser invokes the targeted application inside the browser window. Lastly, the browser sends a third GET request, and this time the browser renders the content of the server file inside the browser and completes the process.
Internet Explorer 5.5 uses the same method but sends two GET requests instead of three.
If possible, configure the plug-in to operate as a helper application instead. Some plug-ins may not work in this mode, but it is a confirmed solution for PDF files and the Adobe Acrobat Reader.
Sample Solution for a PDF FileAccess the PDF file through an HTML page that uses the <OBJECT> tag to specify the ActiveX control version of the PDF viewer as follows:
STYLE="height:100%; width: 100%" >
<PARAM NAME="src" VALUE="http://server/path/filename.pdf">
Steps to Reproduce Behavior
- Request a plug-in readable file from a server (for example, a .pdf file).
- Use the Network Monitor tool to capture the network traffic.
- Filter the result by only selecting the HTTP protocol. Notice that three GET requests are generated to retrieve a single PDF file.
Support WebCast: MIME Type Handling in Microsoft Internet Explorer
Article ID: 293792 - Last Review: May 23, 2007 - Revision: 1