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帮帮忙找找错误

来源：6-11 编程练习

暴走小短腿儿

2019-01-15 21:00

<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
   function count(){
    var x,y,v,r;
    x=document.getElementById(txt1).value;
y=document.getElementById(txt2).value;
v=document.getElementById(select).value;
    switch(v){
        case"+":r=x+y;break;
        case"-":r=x-y;break;
        case"*":r=x*y;break;
        case"/":r=x/y;break;
    }
    document.getElementById(fruit).value=r;

   }
</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>

写回答关注

6回答

Hesher_17

2019-02-16 10:58:12

document.getElementById("fruit").value=r;

0 0
qq_慕丝5117592

2019-01-21 16:03:00

document.getElementById(select).value 你这样是取不到值得

0 0
Chancellor_

2019-01-18 11:58:40

<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var ans;
var one=document.getElementById("txt1").value;
//获取第一个输入框的值
var two=document.getElementById("txt2").value;
//获取第二个输入框的值
var choose=document.getElementById("select").value;
//获取选择框的值
switch(choose)
{
case "+":
ans = parseInt(one)+parseInt(two);
break;
case "-":
ans = parseInt(one)-parseInt(two);
break;
case "*":
ans = parseInt(one)*parseInt(two);
break;
case "/":
ans = parseInt(one)/parseInt(two);
break;
}
//获取通过下拉框来选择的值来改变加减乘除的运算法则
document.getElementById("fruit").value = ans;
//设置结果输入框的值

}
</script>
</head>
<body>
数字：<input type='text' id='txt1' />
<select id='select'>
<option value='+'>+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select><br>
数字：<input type='text' id='txt2' /> <br>
<input type='button' value=' = ' onclick="count()"/> 
<input type='text' id='fruit' />
</body>
</html>

0 2
苏苏酱

2019-01-17 16:39:42

x=document.getElementById(txt1).value;//ID没加引号；

0 0
Dino昵称已占用

2019-01-16 22:07:29

<!DOCTYPE html>
<html>
<head>
<title> 事件</title>
<script type="text/javascript">
function count(){
var x,y,v,r;
x=parseInt(document.getElementById("txt1").value);
y=parseInt(document.getElementById("txt2").value);
v=document.getElementById("select").value;
switch(v){
case"+":r=x+y;break;
case"-":r=x-y;break;
case"*":r=x*y;break;
case"/":r=x/y;break;
}
document.getElementById("fruit").value=r;

}
</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>

0 0
慕移动5083425

2019-01-16 11:19:21

给你个参照
<script type="text/javascript">
function count(){

//获取第一个输入框的值
var a=document.getElementById("txt1").value;
//获取第二个输入框的值
var b=document.getElementById("txt2").value;
//获取选择框的值
var c=document.getElementById("select").value;
//获取通过下拉框来选择的值来改变加减乘除的运算法则
var d="";
switch(c){
case "+":
//d=a+b;
d=parseInt(a)+parseInt(b);
break;
case "-":
d=a-b;
break;
case "*":
d=a*b;
break;
default :
d=a/b;
}
//设置结果输入框的值
document.getElementById("fruit").value=d;
}

0 0