JavaScript - Filtro en javascript con split

<?php

$ko=array("ya", "la", "las", "su", "da", "de", "del", "di", "la", "el", "al", "con", "y", "para", "en", "desde", "por", "los", "en", "días", "dias", "a", "un", "una", "dos", "tres", "ante", "in", "day", "for", "the", "and", "by");

# Creamos el array de la variable recibida

$cadena=explode(" ",$_POST["texto"]);

# Eliminamos los valores repetidos entre los dos arrays

$diff=array_diff($cadena,$ko);

# Pasamos el array a texto

$resultado=implode(" ",$diff);

?>

<?php

require_once('../config.php');

$respuesta="false";

$pregunta = $_POST['pregunta'];

$mail2 = $_POST['mail'];

// $ko=array("ya", "la", "las", "su", "da", "de", "del", "di", "la", "el", "al", "con", "y", "para", "yo", "desde", "por", "los", "en", "días", "dias", "a", "un", "una", "dos", "tres", "ante", "que", "cual", "como", "y", "o", "es");

$cadena=explode(" ",$pregunta);

$largo = sizeof($cadena);

// $diff=array_diff($cadena,$ko);

$vdd=0;

$fal=0;

for($i=0;i<$largo;$i++){

$mysql_query = mysql_query("Select respuestas from preguntas where preguntas = '".$cadena[i]."' " );

$mensaje = mysql_fetch_assoc($mysql_query);

$mensaje_final = $mensaje['respuestas'];

$mysql_query2 = mysql_query("Select preguntas from preguntas where preguntas = '".$cadena[i]."' " );

$mensaje2 = mysql_fetch_assoc($mysql_query2);

$mensaje_final2 = $mensaje2['preguntas'];

if($cadena[i] == $mensaje_final2){

$vdd++;

}else{

$fal++;

}

}

if($vdd>0){

$asunto = "Posible Respuesta";

$mail_para = "xxx@xx.xx";

$header="from:Anon <$mail_para>";

$para = $mail2;

$send = mail($para,$asunto,$mensaje_final,$header);

$respuesta = "true";

}else{

$respuesta = "false";

}

echo ($respuesta);

?>