javascript - 如何在没有jquery的情况下从ajax responseText中获取html元素的数据

Question

我想从ajax响应中获取数据，但此代码不起作用:

var request = new XMLHttpRequest();
request.open("GET", "http://localhost/test/test.php", true);
request.send(null);
request.onreadystatechange = function() {
    if (request.readyState == 4) {
        alert(request.responseText.document.getElementById('div1').innerHTML);
    }   
}

控制台显示此错误:

Uncaught TypeError: Cannot read property 'getElementById' of undefined.

你知道是什么原因造成的吗？

Answer 1

您可以使用DOMParser将html字符串转换为文档片段

var request = new XMLHttpRequest();
request.open("GET", "http://localhost/test/test.php", true);
request.send(null);
request.onreadystatechange = function() {
  if (request.readyState == 4) {
    var parser = new DOMParser();
    var doc = parser.parseFromString(request.responseText, "text/html");
    var elem = doc.getElementById("div1");
    alert(elem.innerHTML);
  }
}

或者，您可以将 responseType 设置为 document

var request = new XMLHttpRequest();
request.open("GET", "file.html", true);
request.responseType = "document";
request.send(null);
request.onreadystatechange = function() {
  if (request.readyState == 4) {
    var doc = request.response;
    var elem = doc.getElementById("div1");
    alert(elem.innerHTML);
  }
}

plnkr http://plnkr.co/edit/lkpveDD31fYY1gmflK9W?p=preview