How to get innerHTML of XML tag has specific id attribute using php? -

having xml file, how can content with/without attribute? example having as:

<book id="1">   <title>...</title>   <author>...</author> </book> <book id="2">   <title>...</title>   <author>...</author> </book> <book id="3">   <title>...</title>   <author>...</author> </book> 

giving input tagname book , id 2, should return inside it, in case:

<title>...</title> <author>...</author> 

i have solved problem looking xml file string , working string want ask possible using xml-file without scroll directly content. in real have big xml file (something 30-40 mb) , want search content in giving coordinates tag-name , (if present) attribute/s. structure of file not "constant".

domxpath::query method filter selected elements xpath. can select elements has specific attribute. code find book tag value of id attribute of 2.

$dom = new domdocument; $dom->loadxml($str);  $xpath = new domxpath($dom); $book = $xpath->query("//book[@id='2']")->item(0);  foreach($book->childnodes $node) {    @$html .= $dom->savehtml($node); } echo $html; 

note final part of code loop through childs of selected element html of them.

check result in demo