优化csv导出默认为不转码

Application/Admin/Common/extend.php

@@ -1748,7 +1748,8 @@ function data2csv(&$data,$title,$fields){
     foreach ($data as $row) {
         $a = [];
         foreach($field as $k=>$v){
-            $a[$v] = $row[$v] . "\t";//防止格式错误
+            // $a[$v] = $row[$v] . "\t";//防止格式错误
+            $a[$v] = $row[$v];
         }
         if ($index == 10000) { //每次写入1000条数据清除内存
             $index = 0;