How to close my dropdown menu? (onclick) - html

Question

I have tried my best to do it myself, but I haven't succeeded. I want the categories (archive, topic etc.) to be able to disappear on my phone when i'm clicking on it the second time. So basically when I click on "Archive" etc. I want it to close again after opening it when I click on it. How do I do that?
My codes:
#primary_nav_wrap
{
margin-top:0;
width: 100%;
}
#primary_nav_wrap ul
{
list-style:none;
position:relative;
float:left;
margin:0;
padding:2.5% 0 0 0;
}
#primary_nav_wrap ul a
{
display:block;
color:#5e5e5e;
text-decoration:none;
font-size:70%;
line-height:32px;
padding:5px 15px;
font-family:'Source Sans Pro', sans-serif;
text-transform: uppercase;
letter-spacing: 3px;
}
#primary_nav_wrap ul li
{
position:relative;
float:left;
margin:0;
padding:0
}
#primary_nav_wrap ul li.current-menu-item
{
background:#FFF;
}
#primary_nav_wrap ul li:hover
{
background:none;
}
#primary_nav_wrap ul ul
{
display:none;
position:absolute;
top:100%;
left:0;
background:#fff;
padding:0;
margin:0;
border: 1px solid #eaeaea;
}
#primary_nav_wrap ul ul li
{
float:none;
width:200px;
}
#primary_nav_wrap ul ul a
{
line-height:120%;
padding:10px 15px;
letter-spacing: 1px !important;
}
#primary_nav_wrap ul ul ul
{
top:0;
left:100%
}
#primary_nav_wrap ul li:hover > ul
{
display:block
}
<nav id="primary_nav_wrap">
<ul>
<li class="current-menu-item">Topic</li>
<li>Archive
<ul>
<li>Sub Menu 1</li>
<li>Sub Menu 2</li>
<li>Sub Menu 3</li>
<li>Sub Menu 4
<ul>
<li>Deep Menu 1
<ul>
<li>Sub Deep 1</li>
<li>Sub Deep 2</li>
<li>Sub Deep 3</li>
<li>Sub Deep 4</li>
</ul>
</li>
<li>Deep Menu 2</li>
</ul>
</li>
<li>Sub Menu 5</li>
</ul>
</li>
<li>Menu 2
<ul>
<li>Sub Menu 1</li>
<li>Sub Menu 2</li>
<li>Sub Menu 3</li>
</ul>
</li>
<li>Menu 3
<ul>
<li class="dir">Sub Menu 1</li>
<li>Sub Menu 3</li>
<li>Sub Menu 4</li>
<li>Sub Menu 5</li>
</ul>
</li>
</ul>
</nav>