Question

我正在尝试制作一个使用JavaScript解决二次方程式的程序。这是我的代码：

"use strict";
function calculation()
{
var a, b , c , delta , x1, x2;
a = Number(document.getElementById("a").value);
b = Number(document.getElementById("b").value);
c = Number(document.getElementById("c").value);
delta = Math.pow(b,2)-4*a*c;
x1 = (-1*b + Math.sqrt(delta))/(2*a);
x2 = (-1*b - Math.sqrt(delta))/(2*a);
document.getElementById("result").value= x1;
document.getElementById("result1").value= x2;
if(delta<0)
{  document.getElementById("result").value= "No real solution"
   document.getElementById("result1").value= "No real solution"
}
if(delta==0)
   {var result2 = b*(-1)/(2*a)
    document.getElementById("result").value = result2
    document.getElementById("result1").value = "No real solution"
    }
if(delta>0)
    {
    document.getElementById("result").value = result
    document.getElementById("result1").value = result1
        }
if(a==0)
    {document.getElementById("message").innerHTML="This is not a quadratic equation"
    document.getElementById("result").value= "No real solution"
    document.getElementById("result1").value= "No real solution"
   }
else {
    document.getElementById("result").value = result
    document.getElementById("result1").value = result1
    }
}

但是，它仅输出[object HTMLInputElement]。为什么会这样？

Answer 1

如果没有HTML部分，很难说出来，但是似乎您从未启动result和result1变量。

Answer 2

"use strict";
function calculation()
{
var a, b , c , delta , x1, x2;
a = Number(document.getElementById("a").value);
b = Number(document.getElementById("b").value);
c = Number(document.getElementById("c").value);
delta = Math.pow(b,2)-4*a*c;
x1 = (-1*b + Math.sqrt(delta))/(2*a);
x2 = (-1*b - Math.sqrt(delta))/(2*a);

// YOU ARE SETTING THE RESULT VALUES HERE ASSUMING THEY ARE GOOD
// document.getElementById("result").value= x1;
// document.getElementById("result1").value= x2;

if(delta<0)
{  document.getElementById("result").value= "No real solution"
   document.getElementById("result1").value= "No real solution"
}
if(delta==0)
   {var result2 = b*(-1)/(2*a)
    document.getElementById("result").value = result2
    document.getElementById("result1").value = "No real solution"
    }
if(delta>0)
    {
    document.getElementById("result").value = x1; // HERE TOO USE VARIABLE NOT OBJECT
    document.getElementById("result1").value = x2; // HERE TOO USE VARIABLE NOT OBJECT
        }
if(a==0)
    {document.getElementById("message").innerHTML="This is not a quadratic equation"
    document.getElementById("result").value= "No real solution";
    document.getElementById("result1").value= "No real solution";
   }
// THESE ARE THE LINES SAYING .value = an html object.
// else {
//     document.getElementById("result").value = result
//     document.getElementById("result1").value = result1
//     }

// RECOMMEND ONLY SETTING IF YOU DETERMINE VALUES ARE USEFUL AND SETTING .value = variable
else {
    document.getElementById("result").value = x1;
    document.getElementById("result1").value = x2;
    }
}

JavaScript问题中的二次方程求解器

2 个答案: