Fixing strings comparation

site/docs/extensions/multiple-sort.md

@@ -38,6 +38,16 @@ toc: true
 
 - **Default:** `true`
 
+### multiSortStrictSearch
+
+- **type:** `Boolean`
+
+- **Detail:**
+
+   Set true to enable strict search. This means that strings will be compared using toLowerCase.
+
+- **Default:** `false`
+
 ### sortPriority
 
 - **type:** `Object`

src/extensions/multiple-sort/bootstrap-table-multiple-sort.js

@@ -432,6 +432,7 @@ $.fn.bootstrapTable.methods.push('multipleSort')
 $.extend($.fn.bootstrapTable.defaults, {
   showMultiSort: false,
   showMultiSortButton: true,
+  multiSortStrictSearch: false,
   sortPriority: null,
   onMultipleSort () {
     return false
@@ -628,6 +629,11 @@ BootstrapTable.prototype.onMultipleSort = function () {
         aa = aa.toString()
       }
 
+      if (that.options.multiSortStrictSearch) {
+        aa = aa.toLowerCase()
+        bb = bb.toLowerCase()
+      }
+
       arr1.push(
         order * cmp(aa, bb))
       arr2.push(