diff --git a/exec/nodelist-html.js b/exec/nodelist-html.js
index 694d5ddfc9f50c0df1f17fcd16a0252e3e16a292..56b92a4fb9405456b55ae188fcf992158b663d39 100644
--- a/exec/nodelist-html.js
+++ b/exec/nodelist-html.js
@@ -125,6 +125,7 @@ for(n=0;n<system.node_list.length;n++) {
 				,user.gender
 				));
 		t=time()-user.logontime;
+        if(t<0) t=0;
 		write(format(
 			"<td align=center>%u:%02u:%02u"
 			,Math.floor(t/(60*60))