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I don't know why it doesn't work

2022-01-27 01:23:07 【CSDN Q & A】

First number
The second number 
<input type="button" id="b"  value="-"><input type="button"  id="c"  value="x"><input type="button" id="d"  value="/"> The result of the calculation is <input type="text" id="jg" >


Refer to the answer 1：

Reference resources ：

<!DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0, user-scalable=no"/>    <meta http-equiv="X-UA-Compatible" content="ie=edge">    <title> Add, subtract, multiply, divide ( Radio box not selected )</title>    <style>                </style></head><body>    <form action="" method="post" name="myform" id="myform">        <div class="wrapper" id="_wrapper">                         Operands 1：<input type="text" name="number1" id="number1" autocomplete="off"/><br><br>            <input type="radio" name="count" id="" value=" Add "/> Add             <input type="radio" name="count" id="" value=" Subtraction "/> Subtraction             <input type="radio" name="count" id="" value=" Multiplication "/> Multiplication             <input type="radio" name="count" id="" value=" division "/> division <br><br>             Operands 2：<input type="text" name="number2" id="number2" autocomplete="off"/><br><br>                            <input type="button" value=" Calculation " id="" onclick="jisuan()"/>            <input type="reset" value=" Reset " id="" /><br><br>             The result of the calculation is ：<input name="txtResult" type="text" id="txtResult" autocomplete="off"/>                    </div>    </form>    <script> var str; var num1 = 0; var num2 = 0; // Click event  //document.form Of name value .input Of name value .value function jisuan(){ str = document.getElementsByName('count'); num1 = parseFloat(document.myform.number1.value); num2 = parseFloat(document.myform.number2.value); // Determine whether the text box is empty  // Note that the text box here uses parseFloat transformation , So when the text box is empty NaN, Not at all "" and null, So you need to use isNaN To judge . if(isNaN(num1) && isNaN(num2)){ alert(" Please fill in the data ！"); } else if(isNaN(num1)){ alert(" Please fill in the operand 1！"); } else if(isNaN(num2)){ alert(" Please fill in the operand 2！"); } else{ danxuankuang(); } if(str[0].checked == true){ document.myform.txtResult.value=num1+num2; } if(str[1].checked == true){ document.myform.txtResult.value=num1-num2; } if(str[2].checked == true){ document.myform.txtResult.value=num1*num2; } if(str[3].checked == true){ document.myform.txtResult.value=num1/num2; } } // Determine whether the radio box is selected  function danxuankuang(){ var a=5;// Define third party variables , Set a value that is not within the value of the radio box  for(var i=0;i < str.length; i ++){ if(str[i].checked == true){ a=i; return a; } } if(a==0 || a==1 || a==2 || a==3){ }else{ alert(" Please select the radio box first ！"); } } </script></body></html>


Refer to the answer 2：


Refer to the answer 3：

js What about code? ？ Use... When publishing </> Format the code



Refer to the answer 4：


Refer to the answer 5：

First number
The second number 
<input type="button" id="b"  value="-" onclick="bb()"><input type="button"  id="c"  value="x" onclick="cc()"><input type="button" id="d"  value="/" onclick="dd()"> The result of the calculation is <input type="text" id="jg" >


Refer to the answer 6：

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