Update README.md

Author: tonystar

README.md

@@ -10,6 +10,8 @@ Bulletproof CSS-only implementation of Float Label pattern with automatic fallba
 
 No-dependencies demo: https://codepen.io/tonystar/pen/JRLaKw.
 
+Bootstrap 3 demo: https://codepen.io/tonystar/pen/ALaZrV.
+
 Bootstrap 4 demo: https://codepen.io/tonystar/pen/LRdpYZ.
 
 
@@ -31,11 +33,15 @@ Wrap `input` and `label` by `.has-float-label`:
 **NOTE:** `label` should go after `input`! This is the only drawback in this method.
 
 
-### Bootstrap 4 quick use
+### Quick use: Bootstrap
 
 Instead of `float-label.min.css` just include pre-built `bootstrap-float-label.min.css`:
 ```html
+<!-- Bootstrap v4 -->
 <link rel="stylesheet" href="https://cdn.rawgit.com/tonystar/bootstrap-float-label/v4.0.0/dist/bootstrap-float-label.min.css"/>
+
+<!-- Bootstrap v3 -->
+<link rel="stylesheet" href="https://cdn.rawgit.com/tonystar/bootstrap-float-label/v3.0.0/dist/bootstrap-float-label.min.css"/>
 ```
 
 Markup is the same. For more details see: https://github.com/tonystar/bootstrap-float-label.