Allow multiple selection of checkboxes holding shift key

Improved usability of the checkboxes in ticket bulk update form, as
well as in many administration pages, by allowing to select range of
checkboxes by holding shift key.

share/static/css/elevator-light/misc.css

@@ -183,3 +183,8 @@ ul.ui-autocomplete {
 .modal.search-results-filter .modal-dialog {
     margin: 0;
 }
+
+/* Enable checkboxes to be selected holding shift key */
+input[type="checkbox"] {
+    z-index: 1;
+}

share/static/js/util.js

@@ -254,6 +254,30 @@ function checkboxesToInput(target,checkboxes) {
     tar.val(emails.join(', ')).change();
 }
 
+// Enable multiple checkbox selection holding shift key
+jQuery(function () {
+    var lastCheckedByName = {};
+    jQuery('input[type=checkbox]').click(function (event) {
+        var name = jQuery(this).attr('name');
+        if (name) {
+            // Remove text after "-" from name for better compatibility
+            name = name.replace(/-.*/, '');
+            var lastChecked = lastCheckedByName[name];
+            if (event.shiftKey && name) {
+                if (lastChecked) {
+                    var checkboxes = jQuery('input[type=checkbox][name^=' + name + ']');
+                    var start = checkboxes.index(this);
+                    var end = checkboxes.index(lastChecked);
+                    checkboxes.slice(Math.min(start, end),
+                        Math.max(start, end) + 1).prop('checked',
+                            this.checked);
+                }
+            }
+            lastCheckedByName[name] = this;
+        }
+    });
+});
+
 // ahah for back compatibility as plugins may still use it
 function ahah( url, id ) {
     jQuery('#'+id).load(url);