add 'noFollow' options

demo.html

@@ -18,7 +18,7 @@
       $("form input[type='submit']").click(function() {
         str = this.form.content.value
         $("#content").html(str);
-        $("#content").linkify(toHashtagUrl);
+        $("#content").linkify({hashtagUrlBuilder: toHashtagUrl, noFollow: false});
         return false;
       });
     });

jquery.linkify.js

@@ -1,4 +1,9 @@
-function linkify(string, buildHashtagUrl, includeW3, target) {
+function linkify(string, buildHashtagUrl, includeW3, target, noFollow) {
+  relNoFollow = "";
+  if (noFollow) {
+    relNoFollow = " rel=\"nofollow\"";
+  }
+
   string = string.replace(/((http|https|ftp)\:\/\/|\bw{3}\.)[a-z0-9\-\.]+\.[a-z]{2,3}(:[a-z0-9]*)?\/?([a-z\u00C0-\u017F0-9\-\._\?\,\'\/\\\+&%\$#\=~])*/gi, function(captured) {
     var uri;
     if (captured.toLowerCase().indexOf("www.") == 0) {
@@ -9,11 +14,11 @@ function linkify(string, buildHashtagUrl, includeW3, target) {
     } else {
       uri = captured;
     }
-    return "<a href=\"" + uri+ "\" target=\"" + target + "\" rel=\"nofollow\">" + captured + "</a>";;
+    return "<a href=\"" + uri+ "\" target=\"" + target + "\"" + relNoFollow + ">" + captured + "</a>";
   });
 
   if (buildHashtagUrl) {
-    string = string.replace(/\B#(\w+)/g, "<a href=" + buildHashtagUrl("$1") +" target=\"" + target + "\" rel=\"nofollow\">#$1</a>");
+    string = string.replace(/\B#(\w+)/g, "<a href=" + buildHashtagUrl("$1") +" target=\"" + target + "\"" + relNoFollow + ">#$1</a>");
   }
   return string;
 }
@@ -25,6 +30,7 @@ function linkify(string, buildHashtagUrl, includeW3, target) {
       var buildHashtagUrl;
       var includeW3 = true;
       var target = '_self';
+      var noFollow = true;
       if (opts) {
         if (typeof opts  == "function") {
           buildHashtagUrl = opts;
@@ -38,14 +44,17 @@ function linkify(string, buildHashtagUrl, includeW3, target) {
           if (typeof opts.target == "string") {
             target = opts.target;
           }
+          if (typeof opts.noFollow == "boolean") {
+            noFollow = opts.noFollow;
+          }
         }
       }
       $this.html(
           $.map(
             $this.contents(),
             function(n, i) {
                 if (n.nodeType == 3) {
-                    return linkify(n.data, buildHashtagUrl, includeW3, target);
+                    return linkify(n.data, buildHashtagUrl, includeW3, target, noFollow);
                 } else {
                     return n.outerHTML;
                 }