js: Properly submit multipart/form-data

This is not IE <10 compatible. Fix follows. ;-)

refs #8758

public/js/icinga/events.js

@@ -199,6 +199,7 @@
             var $form = $(event.currentTarget).closest('form');
             var url = $form.attr('action');
             var method = $form.attr('method');
+            var encoding = $form.attr('enctype');
             var $button = $('input[type=submit]:focus', $form).add('button[type=submit]:focus', $form);
             var $target;
             var data;
@@ -230,6 +231,10 @@
                 method = method.toUpperCase();
             }
 
+            if (typeof encoding === 'undefined') {
+                encoding = 'application/x-www-form-urlencoded';
+            }
+
             if ($button.length === 0) {
                 $button = $('input[type=submit]', $form).add('button[type=submit]', $form).first();
             }
@@ -266,14 +271,22 @@
 
                 url = icinga.utils.addUrlParams(url, dataObj);
             } else {
-                data = $form.serializeArray();
+                if (encoding === 'multipart/form-data') {
+                    data = new FormData($form[0]);
+                } else {
+                    data = $form.serializeArray();
+                }
 
                 if (typeof autosubmit === 'undefined' || ! autosubmit) {
                     if ($button.length && $button.attr('name') !== 'undefined') {
-                        data.push({
+                        if (data instanceof FormData) {
-                            name: $button.attr('name'),
+                            data.append($button.attr('name'), $button.attr('value'));
-                            value: $button.attr('value')
+                        } else {
-                        });
+                            data.push({
+                                name: $button.attr('name'),
+                                value: $button.attr('value')
+                            });
+                        }
                     }
                 }
             }

public/js/icinga/loader.js

@@ -100,13 +100,25 @@
                 headers['X-Icinga-WindowId'] = 'undefined';
             }
 
+            // This is jQuery's default content type
+            var contentType = 'application/x-www-form-urlencoded; charset=UTF-8';
+
+            var isFormData = data instanceof FormData;
+            if (isFormData) {
+                // Setting false is mandatory as the form's data
+                // won't be recognized by the server otherwise
+                contentType = false;
+            }
+
             var self = this;
             var req = $.ajax({
                 type   : method,
                 url    : url,
                 data   : data,
                 headers: headers,
-                context: self
+                context: self,
+                contentType: contentType,
+                processData: ! isFormData
             });
 
             req.$target = $target;