diff --git a/asciidoc.py b/asciidoc.py
index c36b3ae..cc3ae14 100755
--- a/asciidoc.py
+++ b/asciidoc.py
@@ -1677,6 +1677,7 @@ class Title:
 class Section:
     '''Static methods and attributes only.'''
     endtags = [] # Stack of currently open section (level,endtag) tuples.
+    ids = [] # List of already used ids.
     def __init__(self):
         raise AssertionError,'no class instances allowed'
     def savetag(level,etag):
@@ -1689,6 +1690,19 @@ class Section:
             writer.write(Section.endtags.pop()[1])
         document.level = level
     setlevel = staticmethod(setlevel)
+    def gen_id(title):
+        id = re.sub('[^a-zA-Z0-9_\.-]+', '-', title).lower()
+        i = 1
+        while True:
+            if i == 1:
+                tid = id
+            else:
+                tid = "-".join([id, str(i)])
+            if tid not in Section.ids:
+                Section.ids.append(tid)
+                return tid
+            i += 1
+    gen_id = staticmethod(gen_id)
     def translate():
         assert Lex.next() is Title
         prev_sectname = Title.sectname
@@ -1712,6 +1726,11 @@ class Section:
                 warning('section title out of sequence: '
                     'expected level %d, got level %d'
                     % (document.level+1, Title.level))
+
+        # Generate ids for sections
+        if 'id' not in AttributeList.attrs:
+            AttributeList.attrs['id'] = Section.gen_id(Title.dict['title'])
+
         Section.setlevel(Title.level)
         Title.dict['sectnum'] = Title.getnumber(document.level)
         AttributeList.consume(Title.dict)
diff --git a/javascripts/toc.js b/javascripts/toc.js
index a8437ba..24ddd68 100644
--- a/javascripts/toc.js
+++ b/javascripts/toc.js
@@ -54,8 +54,6 @@ function generateToc(toclevels) {
   var entries = tocEntries(document.getElementsByTagName("body")[0], toclevels);
   for (var i = 0; i < entries.length; ++i) {
     var entry = entries[i];
-    if (entry.element.id == "")
-      entry.element.id = "toc" + i;
     var a = document.createElement("a");
     a.href = "#" + entry.element.id;
     a.appendChild(document.createTextNode(entry.text));
diff --git a/xhtml11.conf b/xhtml11.conf
index 3d6cfeb..835d76d 100644
--- a/xhtml11.conf
+++ b/xhtml11.conf
@@ -304,21 +304,21 @@ cellspacing="0" cellpadding="4">
 |
 
 [sect1]
-<h2>{id?<a id="{id}"></a>}{numbered?{sectnum} }{title}</h2>
+<h2{id? id="{id}"}>{numbered?{sectnum} }{title}</h2>
 <div class="sectionbody">
 |
 </div>
 
 [sect2]
-<h3>{id?<a id="{id}"></a>}{numbered?{sectnum} }{title}</h3>
+<h3{id? id="{id}"}>{numbered?{sectnum} }{title}</h3>
 |
 
 [sect3]
-<h4>{id?<a id="{id}"></a>}{numbered?{sectnum} }{title}</h4>
+<h4{id? id="{id}"}>{numbered?{sectnum} }{title}</h4>
 |
 
 [sect4]
-<h5>{id?<a id="{id}"></a>}{title}</h5>
+<h5{id? id="{id}"}>{title}</h5>
 |
 
 [header]