JS 在 HTML 中做加减乘除

浏览数：110 / 时间：2015年06月09日



<script type="text/javascript">
function fun(t){
  var fa = parseInt(document.getElementById(‘fa‘).value);
  var fb = parseInt(document.getElementById(‘fb‘).value);
  var fc = document.getElementById(‘fc‘);
  if(isNaN(fa) || isNaN(fb)){
    alert("输入错误，请重新输入");
    return;
  }
  switch(t){
    case 1:
      fc.value = fa + fb;
      break;
    case 2:
      fc.value = fa - fb;
      break;
    case 3:
      fc.value = fa * fb;
      break;
    case 4:
      fc.value = fa / fb;
      break;
  }
}
</script>
</head>
<body>
<input type="text" id="fa" value=""/>
<input type="text" id="fb" value=""/>
<input type="text" id="fc" value=""/>
<input type="button" value="+" onclick="fun(1);" />
<input type="button" value="-" onclick="fun(2);" />
<input type="button" value="x" onclick="fun(3);" />
<input type="button" value="/" onclick="fun(4);" />

HTML 计算器

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>计算器</title>
    </head>
    <script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>
    <script type="text/javascript">
        $(function(){
            $("button").click(function(){
                var first  = parseInt($("#first").val());//获取第一个数的值并转化为数字
                var second = parseInt($("#second").val());//获取第二个数的值并转化为数字
                var sum    = 0;//定义结果值
                var symbol = parseInt($("[type=radio]:checked").val());//获取符号的值
                //通过对符号的判断计算结果
                switch(symbol){
                    case 0:
                        sum = first + second;
                        break;
                    case 1:
                        sum = first - second;
                        break;
                    case 2:
                        sum = first * second;
                        break;
                    case 3:
                        sum = first / second;
                        break;
                }
                var arr    = [‘+‘,‘-‘,‘*‘,‘/‘];//输出的符号
                $("h2 span").text(first + arr[symbol] + second +" = " +sum);//把结果输出到结果栏中 
            })         
        })
    </script>
    <body>
        <h1>计算器</h1>
        <p>数字一：<input type="text" id="first" style="width: 40px;" /></p>
        <p>
            <label><input type="radio" name="symbol" value="0" checked="checked"/>+</label>
            <label><input type="radio" name="symbol" value="1" />-</label>
            <label><input type="radio" name="symbol" value="2" />*</label>
            <label><input type="radio" name="symbol" value="3" />/</label>
        </p>
        <p>数字二：<input type="text" id="second" style="width: 40px;" /></p>
        <p><button>计算</button></p>
        <h2>结果：<span></span></h2>
    </body>
</html>