diff --git a/webtools/bonsai/cvsblame.cgi b/webtools/bonsai/cvsblame.cgi
index 5032041ffdd..b9348efc828 100755
--- a/webtools/bonsai/cvsblame.cgi
+++ b/webtools/bonsai/cvsblame.cgi
@@ -541,6 +541,8 @@ function showMessage(rev,line) {
         r.style.display='none'
     }
     r = document.getElementById('rev_'+rev)
+    if (!r)
+        return
     var l = document.getElementById('line_'+line)
     var t = l.offsetTop
     var p = l.offsetParent
diff --git a/webtools/bonsai/cvsgraph.cgi b/webtools/bonsai/cvsgraph.cgi
index 86ad2d8ef43..5c24ba145b7 100755
--- a/webtools/bonsai/cvsgraph.cgi
+++ b/webtools/bonsai/cvsgraph.cgi
@@ -135,6 +135,8 @@ function showMessage(rev) {
         r.style.display='none'
     }
     r = document.getElementById('rev_'+rev)
+    if (!r)
+        return false
     var l = document.getElementById('link_'+rev)
     var t = l.offsetTop + 20
     r.style.top = t