diff --git a/www/lib.js b/www/lib.js
index ebf888a..9ad619c 100644
--- a/www/lib.js
+++ b/www/lib.js
@@ -1,6 +1,8 @@
 function Lib(ws) {
   return {
     clearElement: clearElement,
+    defaultCompare: defaultCompare,
+    funMap: funMap,
     insert: insert,
     send: send
   };
@@ -11,14 +13,36 @@ function Lib(ws) {
     }
   }
 
-  function insert(obj, t, min, max) {
+  function insert(obj, t, compare, min, max) {
     min = min == undefined ? 0 : min;
     max = max == undefined ? t.length : max;
+    compare = compare == undefined ? defaultCompare : compare;
     if(max - min < 1) {
       return min;
     }
     var avg = Math.floor((max + min) / 2);
-    return (obj < t[avg]) ? insert(obj, t, min, avg) : insert(obj, t, avg+1, max);
+    if (compare(obj, t[avg]) < 0) {
+      return insert(obj, t, compare, min, avg);
+    } else {
+      return insert(obj, t, compare, avg+1, max);
+    }
+  }
+
+  function defaultCompare(a, b) {
+    if(a < b) {
+      return -1;
+    } else if(a > b) {
+      return 1;
+    } else {
+      return 0;
+    }
+  }
+
+  function funMap(projector, f) {
+    return function() {
+      var args = Array.prototype.map.call(arguments, projector);
+      return f.apply(null, args);
+    }
   }
 
   function send(o) {