<p class="shu_ck"> <em class="cc_sub" data-id="71842887">-</em> <input type="number" id="gnum" data-id="71842887" class="gnum c_pt" min="1" value="1"/> <em class="cc_add" data-id="71842887">+</em> </p><p class="shu_ck"> <em class="cc_sub" data-id="71842887">-</em> <input type="number" id="gnum" data-id="71842887" class="gnum c_pt" min="1" value="1"/> <em class="cc_add" data-id="71842887">+</em> </p帮我用上面列子做一个完整PHP的ajx点击回调事件,实现加减计算总和,加一个复选框选中显示的p标签盒子

好的，以下是一个实现您描述的功能的PHP AJAX回调事件的示例代码：

HTML代码：

<p class="shu_ck">                         
    <em class="cc_sub" data-id="71842887">-</em>                         
    <input type="number" id="gnum1" data-id="71842887" class="gnum c_pt" min="1" value="1"/>                         
    <em class="cc_add" data-id="71842887">+</em>
</p>
<p class="shu_ck">                         
    <em class="cc_sub" data-id="71842888">-</em>                         
    <input type="number" id="gnum2" data-id="71842888" class="gnum c_pt" min="1" value="1"/>                         
    <em class="cc_add" data-id="71842888">+</em>
</p>
<input type="checkbox" id="checkbox" onclick="calculateTotal()" />
<p id="total"></p>

JavaScript代码：

function calculateTotal() {
    var total = 0;
    if (document.getElementById("checkbox").checked) {
        var gnum1 = document.getElementById("gnum1").value;
        var gnum2 = document.getElementById("gnum2").value;
        total = parseInt(gnum1) + parseInt(gnum2);
    }
    document.getElementById("total").innerHTML = "总和：" + total;
}

$(document).ready(function() {
    $(".cc_add").click(function() {
        var input = $(this).prev();
        var oldValue = parseInt(input.val());
        if (oldValue < parseInt(input.attr("max"))) {
            var newVal = oldValue + 1;
            input.val(newVal);
        }
        calculateTotal();
    });

    $(".cc_sub").click(function() {
        var input = $(this).next();
        var oldValue = parseInt(input.val());
        if (oldValue > parseInt(input.attr("min"))) {
            var newVal = oldValue - 1;
            input.val(newVal);
        }
        calculateTotal();
    });
});

PHP代码：

<?php

if(isset($_POST['gnum1']) && isset($_POST['gnum2'])) {
    $gnum1 = $_POST['gnum1'];
    $gnum2 = $_POST['gnum2'];
    $total = $gnum1 + $gnum2;
    echo $total;
}

?>

AJAX代码：

function calculateTotal() {
    var gnum1 = document.getElementById("gnum1").value;
    var gnum2 = document.getElementById("gnum2").value;
    var xhr = new XMLHttpRequest();
    xhr.open("POST", "calculate.php", true);
    xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xhr.onreadystatechange = function() {
        if (xhr.readyState == 4 && xhr.status == 200) {
            var total = xhr.responseText;
            document.getElementById("total").innerHTML = "总和：" + total;
        }
    };
    xhr.send("gnum1=" + gnum1 + "&gnum2=" + gnum2);
}

在上面的代码中，我们使用jQuery来捕获“+”和“-”按钮的单击事件，并使用JavaScript计算总和。当复选框被选中时，我们使用AJAX将输入值发送到PHP脚本中进行处理，并在回调函数中将结果显示在页面中。