[jquery] JS jQuery - check if value is in array

I am more of a PHP person, not JS - and I think my problem is more a syntax problem ..

I have a small jQuery to "validate" and check input value .

It works ok for single words, but I need array.

I am using the inArray() of jQuery .

var ar = ["value1", "value2", "value3", "value4"]; // ETC...

        jQuery(document).ready(function() {

            jQuery("form#searchreport").submit(function() {
            if (jQuery.inArray(jQuery("input:first"), ar)){ 
                      //if (jQuery("input:first").val() == "value11") { // works for single words
            jQuery("#divResult").html("<span>VALUE FOUND</span>").show();
            jQuery("#contentresults").delay(800).show("slow");
                return false;
              }

        // SINGLE VALUE SPECIAL CASE / Value not allowed 
               if (jQuery("input:first").val() == "word10") {

                jQuery("#divResult").html("YOU CHEAT !").show();
                jQuery("#contentresults").delay(800).show("slow");

                return false;
              }

        // Value not Valid

              jQuery("#divResult").text("Not valid!").show().fadeOut(1000);

              return false;
            });

        });

now - this if (jQuery.inArray(jQuery("input:first"), ar)) is not working right .. every value that I put will be validated as OK . (even empty)

I need to validate only values from the array (ar) .

I tried also if (jQuery.inArray(jQuery("input:first"), ar) == 1) // 1,0,-1 tried all

what am i doing wrong ?

Bonus question : how to do NOT in array in jQuery ?? (the equivalent of PHP if (!in_array('1', $a)) - I sw somehre that it will not work , and need to use something like this : !!~

The Array.prototype property represents the prototype for the Array constructor and allows you to add new properties and methods to all Array objects. we can create a prototype for this purpose

Array.prototype.has_element = function(element) {
    return $.inArray( element, this) !== -1;
};

And then use it like this

var numbers= [1, 2, 3, 4];
numbers.has_element(3) => true
numbers.has_element(10) => false

See the Demo below

Array.prototype.has_element = function(element) {_x000D_
  return $.inArray(element, this) !== -1;_x000D_
};_x000D_
_x000D_
_x000D_
_x000D_
var numbers = [1, 2, 3, 4];_x000D_
console.log(numbers.has_element(3));_x000D_
console.log(numbers.has_element(10));

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

As to your bonus question, try if (jQuery.inArray(jQuery("input:first").val(), ar) < 0)

Alternate solution of the values check

//Duplicate Title Entry 
    $.each(ar , function (i, val) {
        if ( jQuery("input:first").val()== val) alert('VALUE FOUND'+Valuecheck);
  });