Support Document.prototype.contains in IE

Gruntfile.js

@@ -99,6 +99,7 @@ module.exports = function (grunt) {
       dist: {
         src: ['<%= curl.jschannel.dest %>',
               '<%= curl.domparser.dest %>',
+              'lib/iefix/*.js',
               'renderjs.js'],
         dest: 'dist/<%= pkg.name %>-<%= pkg.version %>.js'
       }

lib/iefix/doccontains.js

+// IE does not support have Document.prototype.contains.
+if (typeof document.contains !== 'function') {
+  Document.prototype.contains = function(node) {
+    if (node === this || node.parentNode === this)
+      return true;
+    return this.documentElement.contains(node);
+ }
+}