String Relace

string_replace.php

function str_lreplace($needle, $replace, $haystack)
{
  /*
	 int strrpos ( string $haystack , string $needle [, int $offset = 0 ] )
	Find the numeric position of the last occurrence of needle in the haystack string. 
	*/	
    $pos = strrpos($haystack, $needle);
    if($pos !== false)
    {
        $subject = substr_replace($haystack, $replace, $pos, strlen($needle));
    }
    return $subject;
}