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JS 在 HTML 中做加减乘除



<
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>

 

JS 在 HTML 中做加减乘除