add wraper only when there is enough elements to wrap. code review by LZF

@@ -50,9 +50,13 @@ function hiddenTips($ele) {
 //}
 
 function wrapElements(selector, count) {
+    var elArr = null;
+
     $(selector).each(function(idx, el) {
-        if (idx % count === 0) {
-            $($(selector).slice(idx, idx + count)).wrapAll($('<div class="js-wraper"></div>'));
+        elArr = $(selector).slice(idx, idx + count);
+
+        if (elArr.length === count && idx % count === 0) {
+            $(elArr).wrapAll($('<div class="js-wraper"></div>'));
         }
     });
 }