Here is example to make Simple and Nice Navbar with Dropdown Menu Using jQuqery


Fire structure:

Jquery-Dropdown/
┣ css/
┃ ┗ style.css
┣ js/
┃ ┗ main.js
┗ index.php

index.php

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title></title>
        <script src="https://code.jquery.com/jquery-1.12.4.js"></script>
        <script src="js/main.js" type="text/javascript"></script>
        <link href="css/style.css" rel="stylesheet" type="text/css"/>
     
    </head>
    <body>
        <nav>
            <header>
                <ul class="left-nav">
                    <li><a href="#">Logo</a></li>
                </ul>

                <ul class="right-nav">
                    <li class="dropdown">
                      
                        <div style="margin-bottom: 10px;">
                              <a href="" id="services">Services</a>
                        </div>
                        <ul class="sub-menu">
                            <li><a href="#">Android Development</a></li>
                            <li><a href="#">Web development</a></li>
                            <li><a href="#">Graphics Design</a></li>
                            <li><a href="#">Training</a></li>
                        </ul>
                    </li>
                    <li><a href="">Portfolio</a></li>
                    <li class="chat"><a href="#" class="minimize-chat">Live Chat</a></li>
                </ul>
            </header>
        </nav>
    </body>
</html>


style.css

body{
    margin: 0;
    padding: 0;
    background: #ebe8e8;
}

nav header{
    background: #928c8c;
    height: 65px;
}

nav header > ul{
    margin: 0;

}

nav header > ul > li{
    margin-top: 20px;
}


ul.right-nav{
    float: right;
}


nav li a{
    text-decoration: none;
    font-family:sans-serif;
    text-transform: uppercase;
    font-weight: 100;
    color: #fff;
    font-size: 14px;
}

nav li{
    list-style-type: none;
    float: left;

    margin-right: 10px;
}

ul.sub-menu {
    position: absolute;
    width: 200px;
    padding: 10px 0px 10px 10px;
    background: #fff;
    display: none;
    padding-top: 10px;
    padding-bottom: 10px;
    box-shadow:0.1px 0.1px 10px rgba(0, 0, 0, 0.1);
    border-radius: 2px;

}
ul.sub-menu li:first-child{
    margin-top: -20px;

}

ul.sub-menu li{
    margin-bottom: 35px;
    position: relative;
}

ul.sub-menu li > a:hover{
    border:none;
    color: #ff9900;

}

ul.sub-menu li  a{
    color: #000;
    text-decoration: none;
}


.sub-menu:before{

    width: 16px;
    height: 16px;
    background-size: 100%;
    background-repeat: no-repeat;
    content: " ";
    display: inline-block;
    position: relative;
    top: -15px;
    left: 5px;
    z-index: 0;
    border-left: 10px solid #fff;
    border-bottom: 10px solid #fff;
    transform: rotate(133deg);
    margin-right: 7px;
    transition: none;
}


main.js

$(document).ready(function () {
    $('.dropdown').hover(function () {
        $(this).children('.sub-menu').slideDown(200);
    },
            function () {
                $(this).children('.sub-menu').slideUp(200);
            }
    );
});