Add focus methods

kfet/static/kfet/js/kpsul.js

@@ -19,6 +19,17 @@ class KPsulManager {
         }
     }
 
+    focus() {
+        if (this.checkout_manager.is_empty())
+            this.checkout_manager.focus();
+        else if (this.account_manager.is_empty())
+            this.account_manager.focus();
+        else
+            this.article_manager.focus();
+
+        return this;
+    }
+
 }
 
 
@@ -267,11 +278,7 @@ class CheckoutManager {
                 (data) => this._update_on_success(data),
                 () => this.reset_data());
 
-        if (kpsul.account_manager.is_empty()) {
-            kpsul.account_manager.focus();
-        } else {
-            kpsul.article_manager.focus();
-        }
+        kpsul.focus();
     }
 
     _update_on_success(data) {
@@ -336,6 +343,11 @@ class CheckoutManager {
 
         this.display();
     }
+
+    focus() {
+        this.selection.focus();
+        return this;
+    }
 }
 
 
@@ -368,6 +380,11 @@ class CheckoutSelection {
     reset() {
         this._$input.find('option:first').prop('selected', true);
     }
+
+    focus() {
+        this._$input.focus();
+        return this;
+    }
 }
 
 class ArticleManager {