While looking into a problem where my pages were showing up blank on IE, Moonfallen pointed me to the NEVERSINGLETON list in t.w.microdom.toxml(). There is a list of elements which should never be rendered as <node/>, and instead should always be <node></node>. Upon looking through the specs for XHTML at w3c.org, however, I found that the _only_ XHTML elements which are allowed as singletons are those whose content models are "EMPTY" -- <br/>, <hr/>, and so on. The list of EMPTY elements is not huge. I understand the issue that microdom cannot get bogged down with HTML tweaks; it is, after all, supposed to produce XML. But it seems like t.w.microdom shouldn't be spitting out invalid XHTML, even if (for now) it doesn't look like it breaks anyone's browser. As I understand it there is no real difference in XML between <node/> and <node></node>. Given that, wouldn't it be better for toxml() to use an ALLOWSINGLETON list instead of NEVERSINGLETON? That is, unless an element is explicitly allowed to be <foo/>, it would be <foo></foo>? If this is of interest to anyone, below is a diff that implements this; the list of elements is from the XHTML 1.0 DTD. I haven't tested it, so someone else will have to do that, but it works on my page. Index: twisted/web/microdom.py =================================================================== RCS file: /cvs/Twisted/twisted/web/microdom.py,v retrieving revision 1.93 diff -u -r1.93 microdom.py --- twisted/web/microdom.py 27 Jun 2003 19:10:35 -0000 1.93 +++ twisted/web/microdom.py 27 Jun 2003 20:16:17 -0000 @@ -449,8 +449,9 @@ def writexml(self, stream, indent='', addindent='', newl='', strip=0): # write beginning - NEVERSINGLETON = ('a', 'li', 'div', 'span', 'title', 'script', - 'textarea', 'select', 'style') + ALLOWSINGLETON = ('img', 'br', 'hr', 'base', 'meta', 'link', 'param', + 'area', 'input', 'col', 'basefont', 'isindex', + 'frame') # this should never be necessary unless people start # changing .tagName on the fly(?) if not self.preserveCase: @@ -468,7 +469,7 @@ for child in self.childNodes: child.writexml(stream, newindent, addindent, newl, strip) w(j((newl, indent, "</", self.endTagName, '>'))) - elif self.tagName.lower() in NEVERSINGLETON: + elif self.tagName.lower() not in ALLOWSINGLETON: w(j(('></', self.endTagName, '>'))) else: w(" />") -- Alex Levy WWW: http://mesozoic.geecs.org "Never let your sense of morals prevent you from doing what is right." -- Salvor Hardin, Isaac Asimov's _Foundation_