added empty sort plugin

sorting/empty-sort.js

@@ -0,0 +1,59 @@
+/**
+ * Sorts cells with empty values by placing them after cells with values
+ * This helps when if you have column that may or may not have values
+ * allowing items with values to appear first when sorting ascending
+ * This was written to help with sorting items that were ranked, where
+ *  items without a rank number were considered lower in rank
+ *
+ *  @name  Empty
+ *  @summary Sort items without a value after items with a value
+ *  @author Timothy Stewart
+ *
+ *  @example
+ *    $('#example').dataTable( {
+ *       columnDefs: [
+ *         { type: 'empty', targets: 0 }
+ *       ]
+ *    } );
+ */
+    function emptySort(x, y) {
+        // this is the value we will end up returning
+        var retVal;
+
+        // replace html spaces with empty, shouldn't happen but just in case
+        x = x.replace(' ', '');
+        y = y.replace(' ', '');
+
+        // test if  a number, if so, set it
+        if (parseInt(x)) {
+            x = parseInt(x)
+        }
+
+        if (parseInt(y)) {
+            y = parseInt(y)
+        }
+
+        // now we need to eval the x,y values and set the order
+        // if blank they will appear last
+        if (x == y) retVal = 0;
+        else if (parseInt(x) && parseInt(y)) {
+            if (x > y) retVal = 1;
+            else retVal = -1;
+        }
+        else if (parseInt(x)) retVal = -1;
+        else if (parseInt(y)) retVal = 1;
+        else if (x > y) retVal = 1;
+        else return -1;
+
+        return retVal;
+    }
+
+    jQuery.extend(jQuery.fn.dataTableExt.oSort, {
+        'empty-asc': function (a, b) {
+            return emptySort(a, b);
+        },
+
+        'empty-desc': function (a, b) {
+            return emptySort(b, a);
+        }
+    });