$(document).ready(function()
{
    const PLAYER = "X";
    const COMPUTER = "O";
    let game_status = true;
    var emptyCells = [];
    var playerPos = [];
    var computerPos = [];

$('.col').click(function() {
    isGameOver(PLAYER);

    //Do Not Click Filled Div
    if ($(this).text().length !== 0) {
        return;
    }

    //Save Player Moves
    playerPos.push([Number($(this).attr("data-x")), Number($(this).attr("data-y"))]);

    //Make Click
    $(this).html(PLAYER);

    //Clear Empty Cells To Fill Later!
    emptyCells = [];

    //Let Computer Move
    computerMove();
});

function computerMove(){
    isGameOver(COMPUTER);

    //Save Computer Moves
    computerPos.push([Number($(this).attr("data-x")),Number($(this).attr("data-y"))]);

    //Add All Empty Cells To An Array
    for(let x=1; x<=4; x++){
        for (let y=1; y<=4; y++) {
            if ($('.col[data-x='+x+'][data-y='+y+']').text().length == 0) {
                emptyCells.push($('.col[data-x='+x+'][data-y='+y+']'));
            }
        }
    }

    //Click Random Empty Cell
    if (emptyCells.length > 0) {
    let computerChoice = emptyCells[Math.floor(Math.random() * emptyCells.length)];
    computerChoice.text(COMPUTER);
    }
}

function isGameOver($req) {

    //THIS IS WHERE I STUCK!

    //Vertical Check

    //Horizontal Check

    //Diagonal Check

}
});

<div class="row">
    <div class="col" data-x="1" data-y="1"></div>
    <div class="col" data-x="1" data-y="2"></div>
    <div class="col" data-x="1" data-y="3"></div>
    <div class="col" data-x="1" data-y="4"></div>
</div>

<div class="row">
    <div class="col" data-x="2" data-y="1"></div>
    <div class="col" data-x="2" data-y="2"></div>
    <div class="col" data-x="2" data-y="3"></div>
    <div class="col" data-x="2" data-y="4"></div>
</div>

<div class="row">
    <div class="col" data-x="3" data-y="1"></div>
    <div class="col" data-x="3" data-y="2"></div>
    <div class="col" data-x="3" data-y="3"></div>
    <div class="col" data-x="3" data-y="4"></div>
</div>

<div class="row">
    <div class="col" data-x="4" data-y="1"></div>
    <div class="col" data-x="4" data-y="2"></div>
    <div class="col" data-x="4" data-y="3"></div>
    <div class="col" data-x="4" data-y="4"></div>
</div>