I am making a blog in which users can leave comments on my posts. I used JavaScript to read the data from the XML file and display it in a div element. However, I can't get the page to save new comments to the XML file, and then rewrite the div contents based on the changed XML file. I know how to edit the XML file, but how do I save it? (Sorry, the code's a little messy)
Source Code:
index.html:
<!DOCTYPE html>
<html lang = "en-US">
<head>
<title>Blog</title>
    <script src = "loadXML.js">
    </script>
    <script>
        function addComment1(form)
        {
        var xmlDoc = loadXMLDoc("one.xml");
        var use = form.user1.value;
        var com = form.comment1.value;
        }
    </script>
    <meta charset = "utf-8"/>
</head>
<body>
    <h1>Posts</h1>
    <br/>
    <!-- A Post -->
    <h2>Comments:</h2>
    <div>
        <p>
            <script>
                var xmlDoc = loadXMLDoc("one.xml");
                var cap = xmlDoc.getElementsByTagName("content");
                for (i = 0; i < cap.length; i ++)
                {
                    document.writeln(xmlDoc.getElementsByTagName("user")[i].firstChild.nodeValue + ":<br/>");
        document.writeln(xmlDoc.getElementsByTagName("content")[i].firstChild.nodeValue + "<br/><hr/>");
                }
            </script>
        </p>
        <form name = "form1">
            <input type = "text" name = "user1"/>
        <input type = "text" name = "comment1" />
            <input type = "submit" value = "Submit" onclick = "addComment1(this.form)"/>
        </form>
    </div>
</body>
</html>
one.xml:
<?xml version="1.0" encoding="utf-8"?>
<comment>
        <user>Gabe Rust</user>
        <content>Hello World!</content>
</comment>
loadXML.js:
function loadXMLDoc(filename)
{
if (window.XMLHttpRequest)
{
        xhttp=new XMLHttpRequest();
}
else // code for IE5 and IE6
    {
        xhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xhttp.open("GET",filename,false);
    xhttp.send();
return xhttp.responseXML;
}
function loadXMLString(txt)
{
    if (window.DOMParser)
{
parser=new DOMParser();
xmlDoc=parser.parseFromString(txt,"text/xml");
}
else // code for IE
    {
xmlDoc=new ActiveXObject("Microsoft.XMLDOM");
        xmlDoc.async=false;
xmlDoc.loadXML(txt);
}
    return xmlDoc;
}