class XmlWriter {
    var $xml;
    var $indent;
    var $stack = array();
    function XmlWriter($indent = '  ') {
        $this->indent = $indent;
        $this->xml = '<?xml version="1.0" encoding="utf-8"?>'."\n";
    }
    function _indent() {
        for ($i = 0, $j = count($this->stack); $i < $j; $i++) {
            $this->xml .= $this->indent;
        }
    }
    function push($element, $attributes = array()) {
        $this->_indent();
        $this->xml .= '<'.$element;
        foreach ($attributes as $key => $value) {
            $this->xml .= ' '.$key.'="'.htmlentities($value).'"';
        }
        $this->xml .= ">\n";
        $this->stack[] = $element;
    }
    function element($element, $content, $attributes = array()) {
        $this->_indent();
        $this->xml .= '<'.$element;
        foreach ($attributes as $key => $value) {
            $this->xml .= ' '.$key.'="'.htmlentities($value).'"';
        }
        $this->xml .= '>'.htmlentities($content).'</'.$element.'>'."\n";
    }
    function emptyelement($element, $attributes = array()) {
        $this->_indent();
        $this->xml .= '<'.$element;
        foreach ($attributes as $key => $value) {
            $this->xml .= ' '.$key.'="'.htmlentities($value).'"';
        }
        $this->xml .= " />\n";
    }
    function pop() {
        $element = array_pop($this->stack);
        $this->_indent();
        $this->xml .= "</$element>\n";
    }
    function getXml() {
        return $this->xml;
    }
}


$xml = new XmlWriter();
$xml->push('root');
$xml->push('node');
$xml->element('text', $_POST['content']);
$xml->pop();
$xml->pop();
$data = $xml->getXml();
$xml_file = fopen("../xml/test.xml", "w+") or die("Can't open XML file"); 
if(!fwrite($xml_file, $data)){ print "Error writing to XML-file"; } 
fclose($xml_file);