javascript - 获取输入并使用它进行计算

Question

我想以 xxxx.xx 或 xx% 的形式从用户处输入折扣，并更改金额的计算方法。

//amount = mrp - discount (if discount is xxxx.xx)
    //amount = mrp - discount * mrp (if discount is xx%)

function doMath() {
  var mrp = parseInt(document.getElementById('inmrp').value);
  var discount = (document.getElementById('indiscount').value).String();
  var dis = discount[2];
  var di = discount[1];
  if (dis = '%' || di = "%") {
    discount = (parseInt(discount))/100;
    amount = mrp - mrp * discount;  
  } else {
    discount = parseInt(discount);
    amount = mrp - discount;
  }
  document.getElementById('outamount').value= amount ;
}

Answer 1

尝试

var di = discount.substr(discount.length - 1);  
  if (di == "%") {
   ..........
   .....

jsfiddle here