JAVASCRIPT How to equal an if value for two or multiple values?

i need a help for javascript.

For example i have an x value and i want to two or multiple values equal to x in if statement.

if x equals to apple or pear or banana it writes "fruits". How can i do this?

I've tried || and && operators. I tried to put "," and ";" between the values.

<form name="formname" action="send.php" method="post" onsubmit="return confirm();">

    Type your name : <input type="text" name="name"><br>

    <input type="submit" value="Send">
</form>

<script>
    function confirm() {
        var x = document.formname.name.value;
        if (x == "") {
            alert("You need to fill here!");
            return false;
        }

        else if (x == "Lisa" /* and a little more names... */) {
            alert("You can't enter here");
            return false;
        }
        else {
            alert("Welcome");
            return false;
        }
    }
</script>

When I put "," between values in "else if" statement and when I type else name from "else if" statement, it writes "You can't enter here" again. But i except it will write "Welcome".