为javascript计算器创建一个清除按钮代码

我有一个任务，我必须使用java脚本和HTML创建一个计算器。我已经编写了足够的代码，当我使用操作符时，它将执行数学运算，但数字不会显示在显示框中。我也不确定如何编码清除按钮和取消按钮。这是外部的JavaScript文件。为javascript计算器创建一个清除按钮代码

var mycalc = new calc(null,null,null); 
    function calc(firstNum,secNum,operator) 
    { 
this.firstNum = firstNum; 
this.secNum = secNum; 
this.operator = operator; 
} 
function numberClick(ref) 
{ 
//alert.ref.value 
if(mycalc.firstNum == null) 
    mycalc.firstNum = ref.value 
else if (mycalc.secNum == null) 
    mycalc.secNum = ref.value //ref.value is the value from the input 
//alert("firstNum" + mycalc.operator.firstNum); 
//alert("secNum") + mycalc.secNum); 
} 
function operatorClick(ref) 
{ 
if (mycalc.operator == null) 
    mycalc.operator = ref.value; 
} 
function calculateResultClick() 
{ 
if (mycalc.operator == "+") 
{ 
    var ans = parseInt(mycalc.firstNum) + parseInt(mycalc.secNum); 
    alert(ans); 
} 
if (mycalc.operator == "-") 
{ 
    var ans2 = parseInt(mycalc.firstNum) - parseInt(mycalc.secNum); 
    alert(ans2); 
} 
if (mycalc.operator == "*") 
{ 
    var ans3 = parseInt(mycalc.firstNum) * parseInt(mycalc.secNum); 
    alert(ans3) 
} 
if (mycalc.operator == "/") 
{ 
    var ans4 = parseInt(mycalc.firstNum)/parseInt(mycalc.secNum); 
    alert(ans4) 
} 
    } 
    function Clear() 
    { 

    }

来源

2013-02-21 kayla atkinson

你能不能给我们的jsfiddle，好吗？ – BenM 2013-02-21 22:09:05

取反：

if(parseInt(mycalc.firstNum)>0){ 
    answer=(mycalc.firstNum-mycalc.firstNum*2) 
} 
if(parseInt(mycalc.firstNum)<0){ 
    answer=(mycalc.firstNum+mycalc.firstNum*2) 
}

清除

mycalc.firstNum=0;

来源

2013-02-21 22:17:03 Markasoftware

<html xmlns="http://www.w3.org/1999/xhtml"> 
<head runat="server"> 
    <title></title> 
    <script language="javascript" type="text/javascript"> 

     function Add() { 
      var x, y, txtResult; 
      x = document.getElementById('txtFirst').value; 
      y = document.getElementById('txtSecond').value; 
      if (x == " " || y == "") { 
       alert("Please enter FirstValue and SecondValue"); 
      } 
      else{ 
      var txtResult = +x + +y; 
      document.getElementById('txtResult').innerHTML = "Result: " + txtResult; 
      } 
     } 

     function Sub() { 
      var x, y, txtResult; 
      x = document.getElementById('txtFirst').value; 
      y = document.getElementById('txtSecond').value; 
      if (x == " " || y == "") { 
       alert("Please enter FirstValue and SecondValue"); 
      } else { 
       var txtResult = +x - +y; 
       document.getElementById('txtResult').innerHTML = "Result: " + txtResult; 
      } 
     } 
     function Mul() { 
      var x, y, txtResult; 
      x = document.getElementById('txtFirst').value; 
      y = document.getElementById('txtSecond').value; 
      if (x == " " || y == "") { 
       alert("Please enter FirstValue and SecondValue"); 
      } else { 
       var txtResult = +x * +y; 
       document.getElementById('txtResult').innerHTML = "Result: " + txtResult; 
      } 
     } 

     function Div() { 
      var x, y, txtResult; 
      x = document.getElementById('txtFirst').value; 
      y = document.getElementById('txtSecond').value; 
      if (x == " " || y == "") { 
       alert("Please enter FirstValue and SecondValue"); 
       } 
      else if (y != 0) { 
       var txtResult = +x/+y; 
        } 
      else { 
       alert("Second Number Should not be Zero"); 
        } 
      document.getElementById('txtResult').innerHTML = "Result: " + txtResult; 
      } 

     function Clear() { 
      document.getElementById('txtFirst').value = ""; 
      document.getElementById('txtSecond').value = ""; 
      document.getElementById('txtResult').value = ""; 

     } 


    </script> 
</head> 
<body> 
    <form id="form1" runat="server"> 
    <div> 
     <label> FirstNumber :</label><br /> 
     <input id="txtFirst" type="text" /><br /> 
     <label> Second Number :</label><br /> 
     <input id="txtSecond" type="text" /><br /> 
     <label id="txtResult"></label><br /> 
     <input id="btnAdd" type="button" value="ADD" onclick="Add()"/> 
     <input id="btnSub" type="button" value="SUB" onclick="Sub()"/><br /> 
     <input id="btnMul" type="button" value="MUL" onclick="Mul()"/> 
     <input id="btnDiv" type="button" value="DIV" onclick="Div()"/> 
     <input id="btnClear" type="button" value="Clear" onclick="Clear()"/> 


    </div> 
    </form> 
</body> 
</html>

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来源

2013-06-10 17:34:12

为javascript计算器创建一个清除按钮代码

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