appenChild不是我的php页面中的函数。

Question

大家好，为什么它返回"appenChild不是一个函数？“

function showBooks(ajax) {
         var books = ajax.responseXML.getElementsByTagName("book");
for (var i = 0; i < books.length; i++) {
    var titleNode  = books[i].getElementsByTagName("title")[0];
    var authorNode = books[i].getElementsByTagName("author")[0];
    var title  = titleNode.firstChild.nodeValue;
    var author = authorNode.firstChild.nodeValue;
    var year = books[i].getAttribute("year");

    var li = document.createElement("li");
    li.innerHTML = title + ", by " + author + " (" + year + ")";
    $("books").appendChild(li);
}

在一个页面中，我没有包括它的工作原理。如果我包含这些js，它就不能工作。我需要所有的javascript

   <script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js"> 
   </script> 
    <script src="js/bootstrap.min.js" ></script>
    <script src="vendor/jquery/jquery.min.js"></script>
    <script src="vendor/bootstrap/js/bootstrap.bundle.min.js"></script>
    <!-- Plugin JavaScript -->
    <script src="vendor/jquery-easing/jquery.easing.min.js"></script>

我不能在javascript上做这么多工作，对不起

Answer 1

$("books")是一个jQuery对象，而不是HTMLElement，所以它没有像appendChild那样的HTMLElement方法。jQuery对象所具有的是$(...).append()，它适用于您的情况：

function showBooks(ajax) {
  var books = ajax.responseXML.getElementsByTagName("book");
  for (var i = 0; i < books.length; i++) {
    var titleNode = books[i].getElementsByTagName("title")[0];
    var authorNode = books[i].getElementsByTagName("author")[0];
    var title = titleNode.firstChild.nodeValue;
    var author = authorNode.firstChild.nodeValue;
    var year = books[i].getAttribute("year");

    var li = document.createElement("li");
    li.innerHTML = title + ", by " + author + " (" + year + ")";
    $("#books").append(li); // use jQuery append method instead of appendChild
  }
}

或者，您可以获取底层HTMLElement，并在其上使用appendChild：

function showBooks(ajax) {
  var books = ajax.responseXML.getElementsByTagName("book");
  for (var i = 0; i < books.length; i++) {
    var titleNode = books[i].getElementsByTagName("title")[0];
    var authorNode = books[i].getElementsByTagName("author")[0];
    var title = titleNode.firstChild.nodeValue;
    var author = authorNode.firstChild.nodeValue;
    var year = books[i].getAttribute("year");

    var li = document.createElement("li");
    li.innerHTML = title + ", by " + author + " (" + year + ")";
    $("#books").get(0).appendChild(li)); // use appendChild on the HTMLElement
  }
}