Index: lib/weblib.php
===================================================================
RCS file: /cvsroot/moodle/moodle/lib/weblib.php,v
retrieving revision 1.1044
diff -u -r1.1044 weblib.php
--- lib/weblib.php	15 Mar 2008 15:01:27 -0000	1.1044
+++ lib/weblib.php	18 Mar 2008 15:21:36 -0000
@@ -4208,15 +4208,22 @@
  * @param string $tooltip a tooltip to add to the button as a title attribute.
  * @param boolean $disabled if true, the button will be disabled.
  * @param string $jsconfirmmessage if not empty then display a confirm dialogue with this string as the question.
+ * @param boolean $preventdoublesubmit if true, then when the form is submitted,
+ * the button is disabled to prevent repeat submissions. Default false.
  * @return string / nothing depending on the $return paramter.
  */
 function print_single_button($link, $options, $label='OK', $method='get', $notusedanymore='',
-        $return=false, $tooltip='', $disabled = false, $jsconfirmmessage='') {
+        $return=false, $tooltip='', $disabled = false, $jsconfirmmessage='', $preventdoublesubmit = false) {
     $output = '';
     $link = str_replace('"', '"', $link); //basic XSS protection
+    if ($preventdoublesubmit) {
+        $onsubmit = ' onsubmit="var inputs=this.getElementsByTagName(\'input\');inputs[inputs.length-1].disabled=true;"';
+    } else {
+        $onsubmit = '';
+    }
     $output .= '<div class="singlebutton">';
     // taking target out, will need to add later target="'.$target.'"
-    $output .= '<form action="'. $link .'" method="'. $method .'">';
+    $output .= '<form action="'. $link .'" method="'. $method .'"' . $onsubmit . '>';
     $output .= '<div>';
     if ($options) {
         foreach ($options as $name => $value) {