​x
 
<!DOCTYPE html>
<html>
<body>
​
<p id="demo"></p>
​
<script>
var xhttp = new XMLHttpRequest();
xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
        myFunction(this);
    }
};
xhttp.open("GET", "books_comment.xml", true);
xhttp.send();
​
function myFunction(xml) {
    var x, i, txt, xmlDoc;
    xmlDoc = xml.responseXML;
    txt = "";
    x = xmlDoc.getElementsByTagName("book")[0].childNodes;
    for (i = 0; i < x.length; i++) { 
        // 只处理注释节点
        if (x[i].nodeType == 8) {
            x[i].insertData(25, "Italian ");
            txt += x[i].data + "<br>";
        }
    }
    document.getElementById("demo").innerHTML = txt; 
}
</script>
​
</body>
</html>
​