xml php DOM从循环中获取每个父节点

I have Xml file like

<tag>
    <item>
        <id>106</id>
        <title>DG</title>
    </item>
    <item>
        <id>105</id>
        <title>AC</title>
    </item>
</tag>

How to put each item id and title tags names to separate array

<?php
$xml = '<tag>
    <item>
        <id>106</id>
        <title>DG</title>
    </item>
    <item>
        <id>105</id>
        <title>AC</title>
    </item>
</tag>';

$dom = new DomDocument();
// $dom->load('xml.xml');
$dom->loadXML($xml);
$xpath = new DOMXPath($dom);

$ExTagsArr = array();
foreach ($xpath->evaluate('//item/*') as $i=>$ExTagArr) {
$ExTagsArr[]=$ExTagArr->nodeName;

print_r($ExTagsArr);
}

i got strange arrays

Array ( [0] => id ) Array ( [0] => id [1] => title ) Array ( [0] => id [1] => title [2] => id ) Array ( [0] => id [1] => title [2] => id [3] => title )

but i need get only

Array
(
    [0] => id
    [1] => title
)
Array
(
    [0] => id
    [1] => title
)

<?php

$xml = '
<tag>
    <item>
    <id>106</id>
    <title>DG</title>
    </item>
    <item>
    <id>105</id>
    <title>AC</title>
    </item>
</tag>
';

$dom = new DomDocument();
$dom->loadXML($xml);

// Using SimpleXML
$root = simplexml_import_dom($dom);
foreach ($root->xpath('//item') as $item) {
    $a = (array) $item;
    var_dump($a);
}

// Using plain DOM
foreach ($dom->getElementsByTagName('item') as $item) {
    $a = array();
    for ($i = 0; $i < $item->childNodes->length; ++$i) {
        $child = $item->childNodes->item($i);
        if ($child->nodeType == XML_ELEMENT_NODE) {
            $a[$child->tagName] = $child->nodeValue;
        }
    }
    var_dump($a);
}

Also take a look at this answer.