javascript - 简单的 JavaScript 计算器 if 语句

Question

我是 JS 新手，但我尝试在计算器中创建一个“if”语句，当乘法或加法等的结果大于 20 时，它会发出警报。计算器工作正常但“if”语句则不然。

JS:

var a,b;
function setValues()
{
    a = Number(document.getElementById("a").value);
    b = Number(document.getElementById("b").value);
}

function sum()
{
    setValues();
    result = a+b;
    alert("the sum is equal to "+result);
}
function rest()
{
    setValues();
    result = a-b;
    alert("the rest is equal to "+result);
}
function mult()
{
    setValues();
    result = a*b;
    alert("the operation is equal to "+result);
}
function div()
{
    setValues();
    result = a/b;
    alert("the operation is equal to "+result);
}

if (result > 20) {
    alert("heyy thats pretty big"); 
}

Answer 1

您的 if 语句应该位于每个运算符函数内，如下所示:

function div()
{
  setValues();
  result = a/b;
  alert("the operation is equal to "+result);
  checkResult(result);
}

function checkResult(result){
  if(result > 20)
    alert("heyy thats pretty big");
}