Dropdown Navigation Menu in WordPress

I have used a navigation menu in my wordpress coding. But dropdown is not working. please help me.

[ Moderator Note: Please post code or markup snippets between backticks or use the code button. ]

index.php
=========

false, ‘theme_location’ => ‘primary’ ) ); ?>

function.php
==========

register_nav_menus( array(

‘primary’ => __( ‘Primary Navigation’, ‘sudipta’ ),
‘service’ => __( ‘Service Include’, ‘sudipta’ ),

) );

style.css
==========

#nav-area {
background-color: #d00013;
float: left;
width: 930px;
margin-top: 17px;
margin-right: 0px;
margin-bottom: 0px;
margin-left: 0px;
padding: 15px;
}

#nav-area ul {
background: url(images/corner-right1.jpg) no-repeat right top;
margin: 0;
list-style-type: none;
padding-top: 0;
padding-right: 10px;
padding-bottom: 0;
padding-left: 10px;
height: 30px;

}

#nav-area ul li {
height: 30px;
float: left;
padding: 0 15px;

}

#nav-area ul li a {
font-size: 18px;
line-height: 30px;
text-decoration: none;
color: #FFF;
position: relative;
}

#nav-area ul li a:hover, #nav-area ul li.current_page_item a {

text-decoration: underline;

}

How I can solve with jquery dropdown navigation menu?

Waiting for solution.