I am using bootstrap v3.0.0. I am aware that this does not support dropdown-submenu. Lot of solutions posted on stackoverflow and other sources provided the "dropdown-submenu" CSS that I added to my Bootstrap.css and also made changes to my HTML.
And here is my HTML:
 <li id="navPayments" class="dropdown">
        <a href="#" class="dropdown-toggle" data-toggle="dropdown">Movies<b class="caret"></b></a>
        <ul class="dropdown-menu">
           <li class="dropdown-submenu">
               <a tabindex="-1" href="#">Scary</a>
               <ul class="dropdown-menu">
                   <li style="display: block; width: 100%">@this.Html.ActionLink("Voilent", "Voilent", "Movies")</li>
                   <li style="display: block; width: 100%">@this.Html.ActionLink("Extortion", "Extortion", "Movies")</li>
                   <li style="display: block; width: 100%">@this.Html.ActionLink("Evil", "Evil", "Movies")</li>
               </ul>
            </li>   
        </ul>
    </li>
Here is the CSS:
.dropdown-submenu{
    position:relative;
}
.dropdown-submenu > .dropdown-menu
{
    top:0;
    left:100%;
    margin-top:-6px;
    margin-left:-1px;
    -webkit-border-radius:0 6px 6px 6px;
    -moz-border-radius:0 6px 6px 6px;
    border-radius:0 6px 6px 6px;
}
.dropdown-submenu:hover > .dropdown-menu{
    display:block;
}
.dropdown-submenu > a:after{
    display:block;
    content:" ";
    float:right;
    width:0;
    height:0;
    border-color:transparent;
    border-style:solid;
    border-width:5px 0 5px 5px;
    border-left-color:#cccccc;
    margin-top:5px;
    margin-right:-10px;
}
.dropdown-submenu:hover > a:after{
    border-left-color:#ffffff;
}
.dropdown-submenu .pull-left{
    float:none;
}
.dropdown-submenu.pull-left > .dropdown-menu{
    left:-100%;
    margin-left:10px;
    -webkit-border-radius:6px 0 6px 6px;
    -moz-border-radius:6px 0 6px 6px;
    border-radius:6px 0 6px 6px;
}
I see the menu Scary inder Movies but it does not bring up the sub-menus when I hover over that. I am not sure what I am missing here. And it also does not show the little right arrow beside "Scary" menu.
 
     
    