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：