diff --git a/htdocs/samples/axes_x_extent.html b/htdocs/samples/axes_x_selection.html
similarity index 89%
rename from htdocs/samples/axes_x_extent.html
rename to htdocs/samples/axes_x_selection.html
index b433824..a71d36e 100644
--- a/htdocs/samples/axes_x_extent.html
+++ b/htdocs/samples/axes_x_selection.html
@@ -7,7 +7,7 @@
     <div id="chart2"></div>
     <div id="chart3"></div>
 
-    <script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>
+    <script src="http://d3js.org/d3.v4.min.js" charset="utf-8"></script>
     <script src="/js/c3.js"></script>
     <script>
 
@@ -21,7 +21,7 @@
         },
         axis: {
           x: {
-            extent: [2, 4.5]
+            selection: [2, 4.5]
           }
         },
         subchart: {
@@ -42,7 +42,7 @@
         axis: {
           x: {
             type: 'timeseries',
-            extent: ['2014-03-01', '2014-04-20']
+            selection: ['2014-03-01', '2014-04-20']
           }
         },
         subchart: {
@@ -60,7 +60,7 @@
         },
         axis: {
           x: {
-            extent: [1, 4.2]
+            selection: [1, 4.2]
           }
         },
         zoom: {
diff --git a/src/config.js b/src/config.js
index d95e2ec..770be08 100644
--- a/src/config.js
+++ b/src/config.js
@@ -13,7 +13,6 @@ c3_chart_internal_fn.getDefaultConfig = function () {
         padding_bottom: undefined,
         resize_auto: true,
         zoom_enabled: false,
-        zoom_extent: undefined,
         zoom_privileged: false,
         zoom_rescale: false,
         zoom_onzoom: function () {},
@@ -112,7 +111,7 @@ c3_chart_internal_fn.getDefaultConfig = function () {
         axis_x_min: undefined,
         axis_x_padding: {},
         axis_x_height: undefined,
-        axis_x_extent: undefined,
+        axis_x_selection: undefined,
         axis_x_label: {},
         axis_y_show: true,
         axis_y_type: undefined,
diff --git a/src/core.js b/src/core.js
index bb6cd0d..71f9000 100644
--- a/src/core.js
+++ b/src/core.js
@@ -283,15 +283,15 @@ c3_chart_internal_fn.initWithData = function (data) {
     // Define g for chart
     $$.initChartElements();
 
-    // Set default extent if defined
-    if (config.axis_x_extent) { $$.brush.extent($$.getDefaultExtent()); }
-
     // Add Axis
     $$.axis.init();
 
     // Set targets
     $$.updateTargets($$.data.targets);
 
+    // Set default extent if defined
+    if (config.axis_x_selection) { $$.brush.selectionAsValue($$.getDefaultSelection()); }
+
     // Draw with targets
     if (binding) {
         $$.updateDimension();
diff --git a/src/subchart.js b/src/subchart.js
index 32017de..e76f17e 100644
--- a/src/subchart.js
+++ b/src/subchart.js
@@ -253,11 +253,11 @@ c3_chart_internal_fn.transformContext = function (withTransition, transitions) {
     $$.context.attr("transform", $$.getTranslate('context'));
     subXAxis.attr("transform", $$.getTranslate('subx'));
 };
-c3_chart_internal_fn.getDefaultExtent = function () {
+c3_chart_internal_fn.getDefaultSelection = function () {
     var $$ = this, config = $$.config,
-        extent = isFunction(config.axis_x_extent) ? config.axis_x_extent($$.getXDomain($$.data.targets)) : config.axis_x_extent;
+        selection = isFunction(config.axis_x_selection) ? config.axis_x_selection($$.getXDomain($$.data.targets)) : config.axis_x_selection;
     if ($$.isTimeSeries()) {
-        extent = [$$.parseDate(extent[0]), $$.parseDate(extent[1])];
+        selection = [$$.parseDate(selection[0]), $$.parseDate(selection[1])];
     }
-    return extent;
+    return selection;
 };