diff --git a/lib/parser/javascript.js b/lib/parser/javascript.js
index 2fe310b8da..1c1c41064c 100644
--- a/lib/parser/javascript.js
+++ b/lib/parser/javascript.js
@@ -194,7 +194,19 @@ FasterReplyParser.prototype.append = function(newBuffer) {
     }
 
     // very large packet
-    this._buffer = Buffer.concat([this._buffer.slice(this._offset), newBuffer]);
+    // check for concat, if we have it, use it
+    if (Buffer.concat !== undefined) {
+        this._buffer = Buffer.concat([this._buffer.slice(this._offset), newBuffer]);
+    } else {
+        var remaining = this._bytesRemaining();
+        var newLength = remaining + newBuffer.length;
+        var tmpBuffer = new Buffer(newLength);
+
+        this._buffer.copy(tmpBuffer, 0, this._offset);
+        newBuffer.copy(tmpBuffer, remaining, 0);
+        
+        this._buffer = tmpBuffer;
+    }
     this._offset = 0;
 };