2 files changed, 15 insertions, 4 deletions
diff --git a/lib/js/urweb.js b/lib/js/urweb.js
index 25ed2f7a..c031678a 100644
--- a/lib/js/urweb.js
+++ b/lib/js/urweb.js
@@ -295,12 +295,12 @@ function dyn(s) {
   populate(x);
 }
 
-function input(t, s) {
+function input(t, s, recreate) {
   var x = document.createElement(t);
   x.dead = false;
   x.signal = ss(s);
   x.sources = null;
-  x.recreate = function(v) { if (x.value != v) x.value = v; };
+  x.recreate = recreate(x);
   populate(x);
   addNode(x);
 
@@ -308,7 +308,7 @@ function input(t, s) {
 }
 
 function inp(s) {
-  var x = input("input", s);
+  var x = input("input", s, function(x) { return function(v) { if (x.value != v) x.value = v; }; });
   x.value = s.data;
   x.onkeyup = function() { sv(s, x.value) };
 
@@ -316,7 +316,7 @@ function inp(s) {
 }
 
 function sel(s, content) {
-  var x = input("select", s);
+  var x = input("select", s, function(x) { return function(v) { if (x.value != v) x.value = v; }; });
   x.innerHTML = content;
   x.value = s.data;
   x.onchange = function() { sv(s, x.value) };
@@ -324,6 +324,15 @@ function sel(s, content) {
   return x;
 }
 
+function chk(s) {
+  var x = input("input", s, function(x) { return function(v) { if (x.checked != v) x.checked = v; }; });
+  x.type = "checkbox";
+  x.checked = s.data;
+  x.onchange = function() { sv(s, x.checked) };
+
+  return x;
+}
+
 function addOnChange(x, f) {
   var old = x.onchange;
   x.onchange = function() { old(); f (); };
diff --git a/lib/ur/basis.urs b/lib/ur/basis.urs
index 45f36ef8..c5251bb8 100644
--- a/lib/ur/basis.urs
+++ b/lib/ur/basis.urs
@@ -631,6 +631,8 @@ con cformTag = fn (attrs :: {Type}) (inner :: {Unit}) =>
 val ctextbox : cformTag [Value = string, Size = int, Source = source string] []
 val button : cformTag [Value = string, Onclick = transaction unit] []
 
+val ccheckbox : cformTag [Value = bool, Size = int, Source = source bool] []
+
 con cselect = [Cselect]
 val cselect : cformTag [Source = source string,
                         Onchange = transaction unit] cselect