สอบถามการใช้งาน Multiple textbox post + For loop หน่อยครับ

<form method="post">
    <div style="padding:10px;cursor:pointer;" id="drag">
        <input type="text" name="textbox[]" autocomplete="off" value="value 1" />
    </div>
    <div style="padding:10px;cursor:pointer;" id="drag">
        <input type="text" name="textbox[]" autocomplete="off" value="value 2" />
    </div>
    <div style="padding:10px;cursor:pointer;" id="drag">
        <input type="text" name="textbox[]" autocomplete="off" value="value 3" />
    </div>
    <div style="padding:10px;cursor:pointer;" id="drag">
        <input type="text" name="textbox[]" autocomplete="off" value="value 4" />
    </div>
    <div style="padding:10px;cursor:pointer;" id="drag">
        <input type="text" name="textbox[]" autocomplete="off" value="value 5" />
    </div>
    <div style="position:absolute;bottom:50px;right:50px;">
        <input type="submit" name="submit" class="waves-effect waves-light btn" value="Submit" t/>
    </div>
</form>
<?php
if($_POST["submit"]){
	for($i=0; $i<count($_POST["textbox"]); $i++) {
		echo ($i+1)." : ".$_POST["textbox"][$i]. "<br />";	
	}
}
?>