<?php
 
$txt = '<div id="central">
<p>O Primeiro conteudo</p>
<h1>O Primeiro n sei oq</h1>
<p>Batatinha quando nasce</p>
<p>Cabooo</p>
</div>';
$arr = get_tag($txt, "p");
 
echo $arr[1]; 
 
function get_tag($txt,$tag){
	$offset = 0;
	$start_tag = "<".$tag;
	$end_tag = "</".$tag.">";
	$arr = array();
	do{
		$pos = strpos($txt,$start_tag,$offset);	
		if($pos){
			$str_pos = strpos($txt,">",$pos)+1;
			$end_pos = strpos($txt,$end_tag,$str_pos);	
			$len = $end_pos - $str_pos;
			$f_text = substr($txt,$str_pos,$len);
			$arr[] = $f_text;
			$offset = $end_pos;
		}
	}while($pos);
	return $arr;
}

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