使用PHP开发一个简易计算器，实现加减乘除等功能

发布时间：2016-07-07 12:51:47 作者：佚名 阅读：(750)
<!DOCTYPE html>

<html lang="en">

<head>

    <meta charset="UTF-8">

    <title>计算器</title>

    <link rel="stylesheet" type="text/css" href="calculator.css">

</head>

<body>

    <div class="input-box" id="input-box">

            <form method="post" action="" onsubmit="return fullEmpty();">

                <h3>PHP版简单计算器</h3>

                <input type="text" name="a" id="a">

                <select name="oprt" id="oprt">

                    <option value="+">+</option>

                    <option value="-">-</option>

                    <option value="*">*</option>

                    <option value="/">/</option>

                    <option value="%">%</option>

                </select>

                <input type="text" name="b" id="b">

                <button type="submit" name="submit">计算</button>

            </form>

    </div>

    <div class="result" id="result"></div>



</body>

<script type="text/javascript" src="calculator.js"></script>

<?php

    if(isset($_POST["a"]) && isset($_POST["b"]) && isset($_POST["oprt"])) {

        $a = $_POST["a"]; //第一个参加运算的数

        $b = $_POST["b"]; //第二个参加运算的数

        $oprt = $_POST["oprt"]; //运算符

        $r = ""; //运算结果



        //输入框记忆功能

        echo "<script>".

            "a.value = '{$a}';".

            "b.value = '{$b}';".

            "oprt.value = '{$oprt}';".

            "</script>";



        if (!is_numeric($a) || !is_numeric($b)) {

            $r = "运算符两边必须是数字";

        } else {

            $a = $a - 0;

            $b = $b - 0;



            switch($oprt) {

                case "+":

                    $r = $a + $b;

                    break;



                case "-":

                    $r = $a - $b;

                    break;



                case "*":

                    $r = $a * $b;

                    break;



                case "/":

                    if($b == 0) {

                        $r = "除数不能为0";

                    } else {

                        $r = $a / $b;

                    }

                    break;



                case "%":

                    if(!is_int($a) || !is_int($b)) {

                        $r = "求余运算符两边必须是整数";

                    } else if($b == 0) {

                        $r = "除数不能为0";

                    } else {

                        $r = $a % $b;

                    }

                    break;



                default:

                    break;

            }

        }



        //如果运算结果是数字,说明输入正常,否则提示输入错误信息

        if(is_numeric($r)) {

            echo "<script>result.innerText = '{$a} {$oprt} {$b} = {$r}';</script>";

        } else {

            echo "<script>result.innerText = '{$r}';</script>";

        }

    }

?>

</html>



JavaScript



var result = document.getElementById("result");



var a = document.getElementById("a");

var b = document.getElementById("b");

var oprt = document.getElementById("oprt");



//当用户试图提交表单时判断输入是否为空

function fullEmpty() {

    if(a.value.length < 1 || b.value.length < 1) {

        alert("输入不能为空");

        return false;

    }

    return true;

}



CSS



*{

    margin: 0;

    padding: 0;

}



.input-box{

    width: 320px;

    margin: 20px auto 0;

    overflow: hidden;

}



.input-box h3{

    width: 100%;

    text-align: center;

}



.input-box input, select, button{

    margin-top: 10px;

}



.input-box input{

    width: 100px;

}



.input-box select, button{

    width: 50px;

}



.result{

    width: 318px;

    height: 100px;

    border: 1px solid #ccc;

    margin: 10px auto 0;

    text-align: left;

}
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使用PHP开发一个简易计算器，实现加减乘除等功能

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