PHP + Javascript - limit characters in multiple text areas within same form

Javascript

 <script language="javascript" type="text/javascript">
	//http://www.phpfreaks.com/forums/javascript-help/%28solved%29-javascript-character-limit-with-multiple-textareas/
	function checkTextArea(id,limit){
		//alert ("id " +id +" limit " + limit);
		if (document.getElementById(id)){
			//alert("id " + id);
			var txt = document.getElementById(id).value;
			if (txt.length>limit){
				//alert ("reached text limit: " + limit + " characters");
				document.getElementById(id).value = txt.substr(0,limit);
			}
			len = document.getElementById(id).value.length;
			//alert ("len: " + len);
			//alert ("limit");
			span_id = "counter" + id;
			//alert ("span_ID " +span_id);
			if (document.getElementById(span_id)){
			  document.getElementById(span_id).innerHTML = "<b>"+(limit-len)+"</b> characters remaining.";
			} // if
		} //if
	} //function
	</script>

PHP

	<?

	foreach($listing_file as $listing_file_row) {
		$row_count++;
		$path_to_file = $site_dir_listing . "/" . $listing_id . "/t_" . $listing_file_row['file_name'];
		$path_to_delete = $file_basedir_listing . "/" . $listing_id . "/" . $listing_file_row['file_name'];

		$file_row_id = $listing_file_row['row_id'];

		//fb ("path_to_file", $path_to_file);

		echo "
		<input name=\"row_id[]\" type=\"hidden\" value=". $file_row_id." >
		<input name=\"path_to_file[]\" type=\"hidden\" value=".$path_to_file." >

		<tr>
			<td width=\"205\"><img src=" . $path_to_file . " /> <br>
			<td >
			photo title*:
			<br>

			<textarea onkeyup=\"checkTextArea('pic".$file_row_id."',90);\" name=\"title[]\" id=\"pic".$file_row_id."\" rows=\"3\" style=\"width: 350px; height: 50px; margin-bottom: 10px;\">".$listing_file_row['title']."</textarea>
              <br><span id=\"counterpic".$file_row_id."\">90 characters total.</span></script>

<br>
			<input type=\"radio\" name=\"default_image\" value=\"$listing_file_row[row_id]\"";

			if($listing_file_row['default_photo']) echo " checked";

			echo "> default photo**

			<a class=\"button\" href=\"?action=delete_photo&path=$path_to_delete&row_id=$file_row_id\"  onclick=\"this.blur();\"><span>Delete</span></a> 

			</td>

		</tr>";
	 }
	?>