为什么innerHTML无法通过AJAX在响应文本中使用HTML元素？

Question

注意：请不要标记此问题[重复]

我正在尝试在我的网站上使用php动态创建Blog帖子。 问题是，当浏览器收到响应时，无法使用'innerHTML'将blogPosts放在我网站上的Tag部分中。

这是我的HTML代码：

<section id="contentSection">
</section>
    <button name="LOAD_MORE_REQUEST" id="LoadMoreButton" onclick="loadContent();" value="loadMoreButton">Load more</button>

CSS代码：

#contentSection{
                height: 1000px;
                width: 100%;
                background-color: white;
                overflow: scroll;
            }

            .ArticleSection1{
                height: 450px;
                width: 48%;
                float: left;
                margin-left: 1.3%;
                margin-bottom: 30px;
                box-shadow: 0px 0px 10px 4px rgb(180, 180, 180);
            }
            .imageDivArticleSection1{
                height: 50%;
                width: 100%;
                overflow: auto;
            }
            .PreviewTextDiv{
                height: 50%;
                width: 100%;
                overflow: auto;
                background-color: rgba(255, 255, 255, 0.904);
            }
            .ArticleSection1 > div > h1{
                padding-left: 2%;
                padding-top: 15px;
                font-size: 28px;
                float: left;
                font-weight: 100;
                display: table-cell;
                font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            }
            .PreviewTextDiv{
                padding-left: 2%;
                padding-top: 15px;
                font-size: 16px;
                float: left;
                font-weight: 100;
                display: table-cell;
                font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            }
            .ArticleSection1 > div > button{
                width: 20%;
                height: 40px;
                font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
                font-weight: 100;
                color: black;
                font-size: 16px;
                border: 1px solid deepskyblue;
                background-color: transparent;
                margin-left: 2%;
                margin-top: 20px;
            }

JS代码：

var loadMoreButton = document.getElementById("LoadMoreButton").value;
    var sendLoadContentRequest = new XMLHttpRequest();
    requestQuery_Data = new FormData();
    requestQuery_Data.append("LOAD_MORE_REQUEST", loadMoreButton);
    sendLoadContentRequest.open("POST", "LoadContent.php", true);
    sendLoadContentRequest.send(requestQuery_Data);
    DefaultText = document.getElementById("contentSection").innerHTML;
    response = sendLoadContentRequest.responseText;
    document.getElementsByTagName("contentSection").innerHTML = DefaultText +  response;

和PHP代码：

<?php
if(isset($_POST["LOAD_MORE_REQUEST"])){
    loadContentOnPage();
}
else{
    echo("Error");
}


function loadContentOnPage(){
    $response = '
    <section class="ArticleSection1">
    <div class="imageDivArticleSection1"></div>
    <div class="PreviewTextDiv">
        <h1>Code editors to use</h1>
        <br>
        <p>
                Though this is the era of visual presentations than the text or articles but even after that many blog-
                -ers and bloging engines use text teditors but if you are and coding your own blogging website you
                may also need to put one on your website though there are many prewritten texteditors are avilable 
        </p>
        <button>Read more</button>
    </div>
</section>
    ';

    for($a = 0; $a < 4; $a++){
        echo($response); 
    }
}

?>

我正在尝试从过去2天开始解决此问题，并且在浏览了大多数问题后才发现“区分大小写”错误。

Answer 1

就像@Patrick Evans提到的那样，您使用的是异步方法，到您的innerHTML行到达时，请求尚未完成

var loadMoreButton = document.getElementById("LoadMoreButton").value;
    var sendLoadContentRequest = new XMLHttpRequest();
    requestQuery_Data = new FormData();
    requestQuery_Data.append("LOAD_MORE_REQUEST", loadMoreButton);
    sendLoadContentRequest.open("POST", "LoadContent.php", true);
    sendLoadContentRequest.send(requestQuery_Data);
    DefaultText = document.getElementById("contentSection").innerHTML;

    sendLoadContentRequest.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("contentSection").innerHTML = DefaultText +  responseText;
       }
    };