哪里错了求解答

源自：6-11 编程练习

哪里错了求解答

<!DOCTYPE html>

<html>

<head>

<title> 事件</title>

<script type="text/javascript">

function count(){

var a=document.getElementById("txt1").value;

var b=document.getElementById("txt2").value;

var c=document.getElementById("select").value;

var result="";

switch(c)

{

case "+":

result=parseFloat(a) + parseFloat(b);

break;

case "-":

result=parseFloat(a) - parseFloat(b);

break;

case "*":

result=parseFloat(a) * parseFloat(b);

break;

default :

result=parseFloat(a) / parseFloat(b);

break;

}

document.getElementById("fruit")=result;

//获取第一个输入框的值

//获取第二个输入框的值

//获取选择框的值

//获取通过下拉框来选择的值来改变加减乘除的运算法则

//设置结果输入框的值

}

</script>

</head>

<body>

<input type='text' id='txt1' />

<select id='select'>

<option value='+'>+</option>

<option value="-">-</option>

<option value="*">*</option>

<option value="/">/</option>

</select>

<input type='text' id='txt2' />

<input type='button' value=' = ' onclick="count()" />

<input type='text' id='fruit' />

</body>

</html>

提问者：cn_cn 2016-03-22 17:01

个回答

一袋大师

2016-03-22 17:35:50

已采纳

document.getElementById("fruit")=result; or document.getElementById("fruit").value = result;

0
guduzhuaimengzhe

2016-03-22 19:03:05

document.getElementById('fruit').value = result;//设置结果输入框的值
赋值时错误

0
AmJanney

2016-03-22 18:27:50

function count(){
var txt1 = parseInt( document.getElementById('txt1').value);//获取第一个输入框的值
var txt2 = parseInt( document.getElementById('txt2').value);//获取第二个输入框的值
var select = document.getElementById('select').value;//获取选择框的值
var result = '';
switch (select)
{
case '+':
result = txt1 + txt2;
break;
case '-':
result = txt1 - txt2;
break;
case '*':
result = txt1 * txt2;
break;
case '/':
result = txt1 / txt2;
break;
}
document.getElementById('fruit').value = result;//设置结果输入框的值
}

0