diff -r 3519f026e7d6 -r 572b096c889a src/Pure/System/web_app.scala
--- a/src/Pure/System/web_app.scala	Tue Aug 06 15:40:51 2024 +0200
+++ b/src/Pure/System/web_app.scala	Tue Aug 06 16:58:05 2024 +0200
@@ -20,6 +20,7 @@
     def name(n: String): Attribute = new Attribute("name", n)
     def value(v: String): Attribute = new Attribute("value", v)
     def placeholder(p: String): Attribute = new Attribute("placeholder", p)
+    def rowspan(n: Int): Attribute = new Attribute("rowspan", n.toString)
 
     val nav = new Operator("nav")
     val header = new Operator("header")
@@ -28,6 +29,11 @@
     val fieldset = new Operator("fieldset")
     val button = new Operator("button")
 
+    val table = new Operator("table")
+    val th = new Operator("th")
+    val tr = new Operator("tr")
+    val td = new Operator("td")
+
     def icon(href: String): XML.Elem =
       XML.Elem(Markup("link", List("rel" -> "icon", "type" -> "image/x-icon", "href" -> href)), Nil)