递归函数返回未定义

在您的职能部门中：

if (taxWage > minWage) {    // calculates tax recursively calling two other functions difference() and taxStep()     tax = tax + difference(taxWage) * taxStep(taxWage);    var newSalary = taxWage - difference(taxWage);    taxes(tax, newSalary); }

您没有从函数或设置中返回值

returnTax

undefined

也许，您想要这样：

if (taxWage > minWage) {    // calculates tax recursively calling two other functions difference() and taxStep()     tax = tax + difference(taxWage) * taxStep(taxWage);    var newSalary = taxWage - difference(taxWage);    return taxes(tax, newSalary); }