diff --git a/includes/pages/user_shifts.php b/includes/pages/user_shifts.php
index e4d20fdc..f6167cb3 100644
--- a/includes/pages/user_shifts.php
+++ b/includes/pages/user_shifts.php
@@ -856,8 +856,8 @@ function make_select($items, $selected, $name, $title = null) {
   $html = '<div id="selection_' . $name . '" class="selection ' . $name . '">' . "\n";
   $html .= implode("\n", $html_items);
   $html .= buttons(array(
-      button("javascript: check_all('selection_" . $name . "')", _("All"), ""),
-      button("javascript: uncheck_all('selection_" . $name . "')", _("None"), "")
+      button("javascript: checkAll('selection_" . $name . "', true)", _("All"), ""),
+      button("javascript: checkAll('selection_" . $name . "', false)", _("None"), "")
   ));
   $html .= '</div>' . "\n";
   return $html;
diff --git a/public/js/forms.js b/public/js/forms.js
index a8c7f6ce..896cbb35 100644
--- a/public/js/forms.js
+++ b/public/js/forms.js
@@ -1,24 +1,28 @@
-function check_all(id) {
+/**
+ * Runs through the DOM under the element with the given id, finds all
+ * checkboxes and sets them to the wanted state.
+ * 
+ * @param String
+ *            id Id of the element containing all the checkboxes
+ * @param Boolean
+ *            checked True if the checkboxes should be checked
+ */
+function checkAll(id, checked) {
 	var obj = document.getElementById(id);
 	var boxes = obj.getElementsByTagName("input");
-	for ( var i = 0; i < boxes.length; i++) {
-		if (boxes[i].type == "checkbox" && !boxes[i].disabled)
+	for (var i = 0; i < boxes.length; i++) {
+		if (boxes[i].type === "checkbox" && !boxes[i].disabled) {
 			boxes[i].checked = true;
-	}
-}
-
-function uncheck_all(id) {
-	var obj = document.getElementById(id);
-	var boxes = obj.getElementsByTagName("input");
-	for ( var i = 0; i < boxes.length; i++) {
-		if (boxes[i].type == "checkbox")
-			boxes[i].checked = false;
+		}
 	}
 }
 
 $(function() {
-	$('form').submit(function(ev) {
-		$('input[type="submit"]').prop("readonly", true).addClass("disabled");
+	/**
+	 * Disable every submit button after clicking (to prevent double-clicking)
+	 */
+	$("form").submit(function(ev) {
+		$("input[type='submit']").prop("readonly", true).addClass("disabled");
 		return true;
 	});
 });