利用javascript、php和ajax实现计算器

计算器和ajax部分：

<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 16-9-2
 * Time: 上午9:20
 *
 * 计算器_GET
 *
 */

?>
<script type="text/javascript">

    function loadXMLDoc(){

        var xmlhttp;
        if(window.XMLHttpRequest)
            xmlhttp=new XMLHttpRequest(); //IE7+ FF GG
        else
            xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");//IE5 6

        xmlhttp.onreadystatechange=function(){

            if(xmlhttp.readyState==4 && xmlhttp.status==200){
                //alert(xmlhttp.responseText);
                document.getElementById("result").value=xmlhttp.responseText;
            }

        }

        data1=document.getElementById("val1").value;
        dtype=document.getElementById("vtp").value;
        data2=document.getElementById("val2").value;

        xmlhttp.open("GET","test.php?data1="+data1+"&dtype="+dtype+"&data2="+data2, true);
        xmlhttp.send();

    }

</script>

<p>

    <input type="text" name="val1" id="val1">

    <select name="vtp" id="vtp">
        <option value="add">+</option>
        <option value="sub">-</option>
        <option value="mul">*</option>
        <option value="del">/</option>
    </select>

    <input type="text" name="val2" id="val2">

    <button id="calcBtn" onclick="loadXMLDoc()">=</button>

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

</p>

　　运算部分：

<?php

$data1=floatval($_GET['data1']);

$dtype=$_GET['dtype'];

$data2=floatval($_GET['data2']);

if($dtype!="add" && $dtype!="sub" && $dtype!="mul" && $dtype!="del")
    die("error");

if(empty($data1) || empty($data2))
    die("error");

if($dtype=="del" && $data2==0)
    die("0");

$rwt=0;

switch($dtype){

    case "add":
        $rwt=$data1 + $data2;
        break;

    case "sub":
        $rwt=$data1 - $data2;
        break;

    case "mul":
        $rwt=$data1 * $data2;
        break;

    case "del":
        $rwt=$data1 / $data2;
        break;

    default:
        $rwt=0;
}

echo $rwt;

实现效果：