javascript const關鍵字不起作用

Question

my.js

function deductions(){
    parseFloat($('#TaxDeduction').val());        // value 5
}

function earning() {
    const itdeduction = deductions();
    var basicsalary = parseFloat($('#BasicSalary').val());  //value 10000
    var da = parseFloat($('#DA').val());       // value 1000
    var totalearning = Math.round((basicsalary+da));   // value 11000
    var it_deduction = Math.round(((totalearning * itdeduction) / 100)); //value 550
    $('#TaxDeduction').html(it_deduction.toFixed(2));
    $('#TaxDeduction').val(it_deduction.toFixed(2)); //value 550 on first mouse over //value 60500 on second mouseover. but  i Need value 550 for n number of mouseover
}

my.html

onmouseover="earning()"      

在這種onmouseover事件中，我在javascript中的const關鍵字不起作用。 否則，每次onmouseover上的TaxDeduction值都會增加。

Answer 1

您錯過了return ：

 return parseFloat($('#TaxDeduction').val());