我是个小小白，刚学习编写小程序。我编写了一个计算成绩的WXS，在WXS内部给变量赋值可以计算出结果，但不能使用WXS之外的变量做运算：

我的WXS如下， 若直接在WXS内给变量 valfhl 赋值可以计算出结果，但将 valfhl放在js文件的DATA中WXS就不能计算出结果。希望获得大神指教

<wxs module="fhl">

    var  listfhl = [ 

                  {   DXDF:100,          FHL: 3940}, 

                  {   DXDF:95,           FHL: 3820}, 

                  {   DXDF:90,           FHL: 3700}, 

                  {   DXDF:85,           FHL: 3450}, 

                  {   DXDF:80,           FHL: 3200}, 

                  {   DXDF:78,           FHL: 3080}, 

                  {   DXDF:76,           FHL: 2960}, 

                  {   DXDF:74,           FHL: 2840}, 

                  {   DXDF:72,           FHL: 2720}, 

                  {   DXDF:70,           FHL: 2600}, 

                  {   DXDF:68,           FHL: 2480}, 

                  {   DXDF:66,           FHL: 2360}, 

                  {   DXDF:64,           FHL: 2240}, 

                  {   DXDF:62,           FHL: 2120}, 

                  {   DXDF:60,           FHL: 2000}, 

                  {   DXDF:50,           FHL: 1890}, 

                  {   DXDF:40,           FHL: 1780}, 

                  {   DXDF:30,           FHL: 1670}, 

                  {   DXDF:20,           FHL: 1560}, 

                  {   DXDF:10,           FHL: 1450},

                  {   DXDF:0,           FHL: 0}

                ];

               var valfhl = 3939;

                var sz = valfhl;

                var dxdf = function () {

                  var dfen = undefined;

                    for (var i = 1; i < listfhl.length; i++){

                      if (listfhl[0].FHL<=sz ) dfen = listfhl[0].DXDF;

                      else if (sz >= listfhl[i].FHL & sz< listfhl[i-1].FHL ) dfen = listfhl[i].DXDF;

                    };   

                return dfen;}

                module.exports = {

                  Mark : dxdf,

                  sz: sz,

                };

    </wxs>