สอบถามเรื่อง str_replace หน่อยครับ คือผมมี text อยู่ชุดนึงแบบนี้ครับ $text = 'width="320" height="290"'; *แต่ทีนี้ค่า width กับ height

<?php
$text = 'width="320" height="290"';

$rep1_start = strpos($text,'width="')+strlen('width="');   
$rep1_end =strpos($text,"\"",$rep1_start);  
$len1 =$rep1_end-$rep1_start;   
$newwidth="500";
$text =substr_replace($text,$newwidth,$rep1_start,$len1);  

$rep2_start = strpos($text,'height="')+strlen('height="');
$rep2_end =strpos($text,"\"",$rep2_start);
$len2 =$rep2_end-$rep2_start;
$newheight="600";
$text =substr_replace($text,$newheight,$rep2_start,$len2);


?>

<?php
function setSize($text,$newwidth,$newheight){
 $nums =substr_count($text,"width"); // นับคำว่า width เพื่อจะกำหนดจำนวนแทนที่
 $start =0;
 for($i=0 ;$i<$nums ;$i++){
	$rep1_start = strpos($text,'width="',$start)+strlen('width="');   
	$rep1_end =strpos($text,"\"",$rep1_start);  
	$len1 =$rep1_end-$rep1_start;   
	$text =substr_replace($text,$newwidth,$rep1_start,$len1);  

	$rep2_start = strpos($text,'height="',$start)+strlen('height="');
	$rep2_end =strpos($text,"\"",$rep2_start);
	$len2 =$rep2_end-$rep2_start;
	$text =substr_replace($text,$newheight,$rep2_start,$len2);
	$start=$rep2_end;
 }
 return $text;
}
// ทดสอบ
$text = 'width="320" height="290"  to width="320" height="290"';
$width="290";
$height="380";
$change = setSize($text,$width,$height);
echo $change;
?>