Answers for "if is in array"

in_array php

<?php
$os = array("Mac", "NT", "Irix", "Linux");
if (in_array("Irix", $os)) {
    echo "Existe Irix";
}
if (in_array("mac", $os)) {
    echo "Existe mac";
}
?>

javascript check if in array

var extensions = ["image/jpeg","image/png","image/gif"];          
if(extensions.indexOf("myfiletype") === -1){
	alert("Image must be .png, .jpg or .gif");
}