diff --git a/lib/less/tree/javascript.js b/lib/less/tree/javascript.js
index dc7910c48..0b0a12944 100644
--- a/lib/less/tree/javascript.js
+++ b/lib/less/tree/javascript.js
@@ -39,7 +39,9 @@ tree.JavaScript.prototype = {
             throw { message: "JavaScript evaluation error: '" + e.name + ': ' + e.message + "'" ,
                     index: this.index };
         }
-        if (typeof(result) === 'string') {
+        if (typeof(result) === 'number') {
+            return new(tree.Dimension)(result);
+        } else if (typeof(result) === 'string') {
             return new(tree.Quoted)('"' + result + '"', result, this.escaped, this.index);
         } else if (Array.isArray(result)) {
             return new(tree.Anonymous)(result.join(', '));