简单的Javascript计算器

Simple Javascript Calculator

本文关键字：计算器 Javascript 简单      更新时间：2023-09-26

我正在努力学习Javascript，我觉得我对基本原理有很好的掌握，但我在让它做我想做的事情时遇到了问题。。例如我正在尝试用html创建一个简单的表单，用于计算2个数字的和。。这是我的html和javascript:

<head>
    <script type="text/javascript">
        function adder(a,b) {
            var a = document.getElementById('firstNum').value;
            var b = document.getElementById('secondNum').value;
            var numbers = new Array(a,b);
            var sum = 0;
            for (i=0; i < numbers.length; i++) {
                sum += parseInt(numbers[i]);
            }
            //this part i need help with
            document.getElementById('answer').write("First Number: " + a + " plus Second Number: " + b + " is " + sum).value; //this part i need help with
    </script>
</head>
<body>
    <form id="additionForm">
        A + B = C : <input type="text" id="firstNum" placeholder="A"> 
        + <input type="text" id="secondNum" placeholder="B">
        <input type="button" id="addBtn" value="Add" onClick="adder();">
        = <input type="text" id="answerswer" placeholder="C">
    </form>
</body>

我的问题是，我不知道如何让javascript覆盖表单输入id=answer的value属性。。或者如果我应该使用Jquery。。提前谢谢。

function adder() {
  var a = parseInt( document.getElementById('firstNum').value, 10);
   var b = parseInt( document.getElementById('secondNum').value, 10);
   var sum = a + b;
  //this part i need help with
  document.getElementById('answer').value = "First Number: " + a + " plus Second Number: " + b + " is " + sum).value; //this part i need help with
}

如果您想修改javascript中的输入字段，只需设置value属性：

document.getElementById('answer').value = "First Number: " + a + " plus Second Number: " + b + " is " + sum;
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