add 'incsearch' option

chrome/content/vimperator/find.js

@@ -111,7 +111,10 @@ function Search() //{{{
     // Called when the user types a key in the search dialog. Triggers a find attempt
     this.searchKeyPressed = function(command)
     {
-        // TODO: check for 'incsearch'
+        if (!vimperator.options['incsearch'])
+            return;
+
+        // FIXME: isn't the global already set here? -- djk
         var backward = vimperator.hasMode(vimperator.modes.SEARCH_BACKWARD);
         this.find(command, backward);
     }

chrome/content/vimperator/options.js

@@ -432,6 +432,12 @@ function Options() //{{{
             default_value: false
         }
     ));
+    addOption(new Option(["incsearch", "is"], "boolean",
+        {
+            short_help: "Show where the search pattern matches as it is typed",
+            default_value: false
+        }
+    ));
     addOption(new Option(["maxhints", "mh"], "number",
         {
             short_help: "Maximum number of simultaneously shown hints",