diff --git a/contrib/cover.js b/contrib/cover.js
index 49cf15e..d508922 100644
--- a/contrib/cover.js
+++ b/contrib/cover.js
@@ -432,7 +432,8 @@ function getSegments(code, lines, count, statementDetails) {
     // Will now be sorted in start order with end as the second sort criterium
     splintered = [];
     for ( i = 0; i < sd.length; i++) {
-        var us = new Array(sd[i].end - sd[i].start + 1);
+        var size = (sd[i].end - sd[i].start + 1 < 0) ? 0 : sd[i].end - sd[i].start + 1;
+        var us = new Array(size);
         for (k = sd[i].end - sd[i].start; k >= 0; k--) {
             us[k] = 1;                
         }