2007 May 11, 8:55Last time, I had written some resource tools to allow me to view and modify Windows module resources in my ultimate and noble quest to
implement the XML content-type fragment in IE7. Using the resource tools I found that MSXML3.DLL isn't signed and that I can replace the XSLT embedded resource with my own, which is great news and
means I could continue in my endevour. In the following I discuss how I came up with this
replacement for IE7's XML source view.
At first I thought I could just modify the existing XSLT but it turns out that it isn't exactly an
XSLT, rather its an
IE5 XSL. I tried using the
XSL to XSLT converter linked to on MSDN, however the resulting document still
requires manual modification. But I didn't want to muck about in their weird language and I figured I could write my own XSLT faster than I could figure out how theirs worked.
I began work on the new XSLT and found it relatively easy to produce. First I got indenting working with all the XML nodes represented appropriately and different CSS classes attached to them to make
it easy to do syntax highlighting. Next I added in some javascript to allow for closing and opening of elements. At this point my XSLT had the same features as the original XSL.
Next was the XML mimetype fragment which uses
XPointer, a framework around various different schemes for naming parts of an XML document. I focused on the
XPointer scheme which is an extended version of
XPath. So I named my first task as getting XPaths working.
Thankfully javascript running in the HTML document produced by running my XSLT on an XML document has access to the original XML document object via the
document.XMLDocument property. From this this I can execute XPaths, however there's no builtin way to map from the XML nodes selected by
the XPath to the HTML elements that I produced to represent them. So I created a recursive javascript function and XSLT named-template that both produce the same unique strings based on an XML node's
position in the document. For instance 'a3-e2-e' is the name produced for the 3rd attribute of the second element of the root element of the XML document. When producing the HTML for an XML node, I
add an 'id' attribute to the HTML with the unique string of the XML node. Then in javascript when I execute an XPath I can discover the unique string of each node in the selected set and map each of
them to their corresponding positions in the HTML.
With the hard part out of the way I changed the onload to get the fragment of the URI of the current document, interpret it as an XPath and highlight and navigate to the selected nodes. I also added
an interactive floating bar from which you can enter your own XPaths and do the same. On a related note, I found that when accessing XML files via the file URI scheme the fragment is stripped off and
not available to the javascript.
The next steps are of course to actually implement XPointer framework parsing as well as the limited number of schemes that the XPointer framework specifies.
xml xpointer msxml res xpath xslt resource ie7 technical browser ie xsl
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