--- loncom/homework/edit.pm	2005/12/01 18:46:31	1.97
+++ loncom/homework/edit.pm	2005/12/15 23:20:55	1.98
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA 
 # edit mode helpers
 #
-# $Id: edit.pm,v 1.97 2005/12/01 18:46:31 albertel Exp $
+# $Id: edit.pm,v 1.98 2005/12/15 23:20:55 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -498,6 +498,37 @@ sub insert_script {
     return "\n<script type=\"loncapa/perl\"></script>";
 }
 
+sub js_change_detection {
+    my $unsaved=&mt("There are unsaved changes");
+    return (<<SCRIPT);
+<script type="text/javascript">
+var clean = true;
+var is_submit = false;
+function compareForm(event_) {
+        if (!event_ && window.event) {
+          event_ = window.event;
+        }
+	if (!is_submit && !clean) {
+            event_.returnValue = "$unsaved";
+            return "$unsaved";
+        }
+}
+function unClean() {
+     clean=false;
+}
+window.onbeforeunload = compareForm;
+</script>
+SCRIPT
+}
+
+sub form_change_detection {
+    return ' onsubmit="is_submit=true;" ';
+}
+
+sub element_change_detection {
+    return ' onchange="unClean();" ';
+}
+
 sub textarea_sizes {
     my ($data)=@_;
     my $count=0;
@@ -516,10 +547,11 @@ sub editline {
     my ($tag,$data,$description,$size)=@_;
     $data=&HTML::Entities::encode($data,'<>&"');
     if ($description) { $description="<br />".$description."<br />"; }
+    my $change_code = &element_change_detection();
     my $result = <<"END";
 $description
 <input type="text" name="homework_edit_$Apache::lonxml::curdepth" 
-       value="$data" size="$size" />
+       value="$data" size="$size" $change_code />
 END
     return $result;
 }
@@ -544,7 +576,7 @@ sub editfield {
     return $description."\n".'&nbsp;&nbsp;&nbsp;<textarea style="width:100%" rows="'.$rows.
 	'" cols="'.$cols.'" name="homework_edit_'.
 	$Apache::lonxml::curdepth.'" id="homework_edit_'.
-	$Apache::lonxml::curdepth.'">'.
+	$Apache::lonxml::curdepth.'" '.&element_change_detection().'>'.
 	&HTML::Entities::encode($data,'<>&"').'</textarea>'.
 	($usehtmlarea?&Apache::lonhtmlcommon::spelllink('lonhomework',
 			 'homework_edit_'.$Apache::lonxml::curdepth):'')."\n";
@@ -652,7 +684,7 @@ sub checked_arg {
 		last;
 	    }
 	}
-	$result.=" />$text</nobr>\n";
+	$result.=&element_change_detection()." />$text</nobr>\n";
     }
     return $result;
 }
@@ -663,7 +695,8 @@ sub text_arg {
     if (!defined $size) { $size=20; }
     my $arg=$token->[2]{$name};
     $result=&mt($description).'&nbsp;<input name="'.&html_element_name($name).
-	'" type="text" value="'.$arg.'" size="'.$size.'" />';
+	'" type="text" value="'.$arg.'" size="'.$size.'" '.
+	&element_change_detection().'/>';
     return '<nobr>'.$result.'</nobr>';
 }
 
@@ -689,7 +722,7 @@ sub select_arg {
 	}
     }
     $result.='<nobr>'.$description.'&nbsp;<select name="'.
-	&html_element_name($name).'">
+	&html_element_name($name).'" '.&element_change_detection().' >
        '.$optionlist.'
       </select></nobr>';
     return $result;
@@ -722,6 +755,7 @@ sub select_or_text_arg {
  	((!$found)?' selected="selected"':'').
  	">".&mt('Type-in value')."</option>\n";
 #
+    my $change_code=&element_change_detection();
     my $element=&html_element_name($name);
     my $selectelement='select_list_'.$element;
     my $typeinelement='type_in_'.$element;
@@ -746,7 +780,7 @@ $optionlist
        value="$typeinvalue" 
 onChange="$hiddenvalue=$typedinvalue;"
 onFocus="$selectedindex=$selecttypeinindex-1;" />
-<input type="hidden" name="$element" value="$selected" />
+<input type="hidden" name="$element" value="$selected" $change_code />
 </nobr>
 ENDSELECTORTYPE
 }