Add support to the float slider

IPython/html/static/widgets/js/widget_float.js

@@ -1,30 +1,34 b''
 // Copyright (c) IPython Development Team.
 // Distributed under the terms of the Modified BSD License.
 
 define([
     "widgets/js/widget",
     "widgets/js/widget_int",
 ], function(widget, int_widgets){
     var IntSliderView = int_widgets.IntSliderView;
     var IntTextView = int_widgets.IntTextView;
 
     var FloatSliderView = IntSliderView.extend({
+        _validate_text_input: function(x) {
+            return parseFloat(x);
+        },
+
         _validate_slide_value: function(x) {
             // Validate the value of the slider before sending it to the back-end
             // and applying it to the other views on the page.
             return x;
         },
     });
 
     var FloatTextView = IntTextView.extend({
         _parse_value: function(value) {
             // Parse the value stored in a string.
             return  parseFloat(value);
         },
     });
 
     return {
         'FloatSliderView': FloatSliderView,
         'FloatTextView': FloatTextView,
     };
 });