Modify function to remain in the same page if the version is changed

Author: steff456

spec/_static/javascripts/version_dropdown.js

@@ -0,0 +1,31 @@
+function add_custom_version_dropdown(json_loc, target_loc, text) {
+
+    var dropdown = document.createElement("div");
+    dropdown.className = "md-flex__cell md-flex__cell--shrink dropdown";
+    var button = document.createElement("button");
+    button.className = "dropdownbutton";
+    var content = document.createElement("div");
+    content.className = "dropdown-content md-hero";
+    dropdown.appendChild(button);
+    dropdown.appendChild(content);
+    console.log('*********');
+    $.getJSON(json_loc, function(versions) {
+        for (var key in versions) {
+            if (versions.hasOwnProperty(key)) {
+                console.log(key, versions[key]);
+                var a = document.createElement("a");
+                a.innerHTML = key;
+                a.title = key;
+                a.href = target_loc + versions[key] + "/{{ pagename }}.html";
+                console.log('----', a.href);
+                content.appendChild(a);
+            }
+        }
+    }).done(function() {
+        button.innerHTML = text;
+    }).fail(function() {
+        button.innerHTML = "Other Versions Not Found";
+    }).always(function() {
+        $(".navheader").append(dropdown);
+    });
+};