var elt = document.getElementById('table');
var xpath = getElementXPath(elt);
alert(xpath);
 
// Get full XPath of an element
function getElementXPath(elt)
{
	var path = "";
	for (; elt && elt.nodeType == 1; elt = elt.parentNode)
	{
		idx = getElementIdx(elt);
		xname = elt.tagName;
		if (idx > 1) xname += "[" + idx + "]";
		path = "/" + xname + path;
	}
 
	return path;	
}
 
// Get Idx of an element
function getElementIdx(elt)
{
    var count = 1;
    for (var sib = elt.previousSibling; sib ; sib = sib.previousSibling)
    {
        if(sib.nodeType == 1 && sib.tagName == elt.tagName)	count++
    }
 
    return count;
}

// Use it before import PHP Simple HTML DOM Parser
$html = file_get_html('http://www.google.com/');
// find a sample element by id
$elt1 = $html->find('#footer', 0);
// find a sample element by tag name
$elt2= $html->find('div', 10);
 
// it will return if found it: //*[@id="footer"] 
$xpath = getElementXPath($elt1);
 
// it will return if found it: html/body/div[10] 
$xpath = getElementXPath($elt2);
 
function getElementXPath($elt)
{
	$path = '';
	$first = TRUE;
	for(; ($elt AND $elt->nodetype == 1); $elt = $elt->parent())
	{
		$xname = $elt->tag;
		$idx = getElementIdx($elt);
 
		if ($first AND isset($elt->attr['id']))
		{
			$path = '//*[@id="' . $elt->attr['id'] . '"]';
			break;
		}
 
		if ($idx > 1)
		{
			$xname .= '[' . $idx . ']';
		}
 
		$path = '/'.$xname.$path;
 
		$first = FALSE;
	}
 
	return $path;
}
 
function getElementIdx($elt)
{
    $count = 1;
    for($sib = $elt->prev_sibling(); $sib ; $sib = $sib->prev_sibling())
    {
        if($sib->nodetype == 1 && $sib->tag == $elt->tag)
        {
        	$count++;
        }
    }
 
    return $count;
}