How to change navigation drop down from hover to click - html

Question

I'm making a responsive navigation bar that has a dropdown that expands when you hover over it. My problem is that this hover feature is not suitable for mobile devices. As such, I am wanting to change my navigation bar to expand on click instead of on hover.
I have tried using the checkbox method but cannot get it to work. I am wanting to only use HTML and CSS if it is possible. Any help will be greatly appreciated!
See it here: JSFiddle
HTML:
<ul id="navigation">
<li>Product 1
<ul>
<li>rx.com </li>
<li>Resources</li>
<li>Copay Cards</li>
</ul>
</li>
<li>Product 2
<ul>
<li>e.com </li>
<li>Resources</li>
<li>Copay Cards</li>
<li>Informational Video</li>
</ul>
</li>
<li>INSOMNIA EDUCATION
<ul>
<li>Complete Night Sleep Resources</li>
<li>sleep.com </li>
</ul>
</li>
<li>PAIN MGMT EDUCATION
<ul>
<li>Safer Pain Management Resources</li>
<li>painmanagement.com </li>
</ul>
</li>
<li>MEDICAL AFFAIRS
<ul>
<li>Request Clinical Reprints</li>
<li>Schedule a Scientific Session </li>
</ul>
</li>
</ul>
CSS:
/* Main Navigation */
#nav {
position:relative;
width:620px;
margin:0 auto;
margin-top:50px;
padding:10px;
}
ul#navigation {
margin:0px auto;
position:relative;
float:left;
}
ul#navigation li {
display:inline;
font-size:12px;
font-weight:bold;
margin:0;
padding:0;
float:left;
position:relative;
}
ul#navigation li a {
width: 234px;
padding:10px 25px;
color: black;
text-decoration:none;
display:inline-block;
background: #ebebeb;
}
ul#navigation li a:hover {
background:#ebebeb;
color:black;
}
ul#navigation li a.first {
border-left: 0 none;
}
ul#navigation li a.last {
border-right: 0 none;
}
ul#navigation li:hover > a {
background:#ebebeb;
}
/* Drop-Down Navigation */
ul#navigation li:hover > ul
{
/*these 2 styles are very important,
being the ones which make the drop-down to appear on hover */
display: block; /* here change visiblity > display */
opacity:1;
}
ul#navigation ul, ul#navigation ul li ul {
list-style: none;
margin: 0;
padding: 0;
/*the next 2 styles are very important,
being the ones which make the drop-down to stay hidden */
/*visibility:hidden;*/
opacity:0;
/*position: absolute; */
display: none; /* change visibility > display */
z-index: 99999;
width:234px;
background:#ebebeb;
}
ul#navigation ul {
top: 43px;
left: 1px;
}
ul#navigation ul li ul {
top: 0;
left: 181px; /* strong related to width:180px; from above */
}
ul#navigation ul li {
clear:both;
width:55px;
}
ul#navigation ul li a {
background:none;
padding:7px 15px;
color:black;
text-decoration:none;
display:inline-block;
border:0 none;
float:left;
clear:both;
width:150px;
}

Answer 1

Add these lines at the bottom of your css file or tag.
.hidden{
display: none;
}
.shown{
display: block;
opacity: 1;
}
The html file:
<li>
<a id="prod1" href="#">Product 1</a>
<ul id="prod1list" class="hidden">
<li>rx.com </li>
<li>Resources</li>
<li>Copay Cards</li>
</ul>
</li>
<script>
document.getElementById('prod1').addEventListener('click', function(e){
e.preventDefault();
document.getElementById('prod1list').classList.toggle('shown');
});
</script>
I tried it and it seems to work fine.