diff --git a/browser/build.js b/browser/build.js
index 46efebc41..0513610c0 100644
--- a/browser/build.js
+++ b/browser/build.js
@@ -54,8 +54,11 @@ var modules = [
 
 var createBitcore = function(opts) {
 
+
+  opts.dir = opts.dir || '';
+
   // concat browser vendor files
-  exec('cd browser; sh concat.sh', puts);
+  exec('cd '+opts.dir+'browser; sh concat.sh', puts);
 
   if (!opts.includeall && (!opts.submodules || opts.submodules.length === 0)) {
     console.log('Must use either -s or -a option. For more info use the --help option');