Arrow turning 180deg when clicking on dropdown menu

Issue

I have a dropdown menu and want the arrow on the right of it to turn 180deg when I click on it! The problem is I've set the arrow in the html and not in the javascript.. But I thought there was maybe a way to put it in the css when going from #navi to #navigation..

Here's my code

<script>
$(document).ready(function(){
  $("#navi").click(function(){
$("#navigation").slideToggle(500);
  });
});
</script>

#navi{
margin-top:10px;
margin-left:20px;
width:170px;
height:30px;
line-height:30px;
padding-left:10px;
overflow:hidden;
color:{color:Navigation};
background:{color:Navigation background};
font-size:12px;
text-align:left;
}
 
#navi i{
position:absolute;
margin-left:77px;
margin-top:10px;
color:{color:Navigation}!important;
font-size:12px;
}
 
#navigation{
margin-top:10px;
margin-left:20px;
width:180px;
overflow:hidden;
display:none;
font-size:12px;
background:{color:Navigation background};
}

 
#navigationin a{
display:block;
font-size:12px;
line-height:18px;
width:180px;
overflow:hidden;
color:{color:Navigation link};
border-bottom:1px solid {color:Wide sidebar background};
padding:5px;
text-align:center;
}
 
#navigationin a:hover{
box-shadow: inset 180px 0 0 0 {color:Wide sidebar background};
color:{color:Hover};
-webkit-transition: all .7s ease-in-out;
-moz-transition: all .7s  ease-in-out;
-o-transition: all .7s  ease-in-out;
transition: all .7s  ease-in-out;
}

#navigationin a{
-webkit-transition: all .7s ease-in-out;
-moz-transition: all .7s  ease-in-out;
-o-transition: all .7s  ease-in-out;
transition: all .7s  ease-in-out;
}

<div id="navi"> NAVIGATION <i class="fa fa-chevron-down"></i></div>
 
<div id="navigation">
 
<div id="navigationin">

Sorry I can't seem to make it work.. Thank you for any help you can give!

(if you want the actual exemple it's on www.typhotoshop.tumblr.com in the left hovering bar)

Solution

All you have to do is , adding css3 transition on your arrow , and adding/removing a custom class to this last to rotate 180° , in which the transition is triggered.

#navi .fa-chevron-down {
  transition: all 0.5s ease;
}
.rtoate180 {
  transform: rotate(180deg);
}

add in js the toggleclass when click on navi

$("#navi .fa-chevron-down").toggleClass("rtoate180");

bellow working snippet :

$(document).ready(function(){
  $("#navi").click(function(){
    $("#navi .fa-chevron-down").toggleClass("rtoate180");
    $("#navigation").stop().slideToggle(500);
  });
});

#navi .fa-chevron-down {
  transition: all 0.5s ease;
}
.rtoate180 {
  transform: rotate(180deg);
}

#navi{
margin-top:10px;
margin-left:20px;
width:170px;
height:30px;
line-height:30px;
padding-left:10px;
overflow:hidden;
color:{color:Navigation};
background:{color:Navigation background};
font-size:12px;
text-align:left;
}
 
#navi i{
position:absolute;
margin-left:77px;
margin-top:10px;
color:{color:Navigation}!important;
font-size:12px;
}
 
#navigation{
margin-top:10px;
margin-left:20px;
width:180px;
overflow:hidden;
display:none;
font-size:12px;
background:{color:Navigation background};
}

 
#navigationin a{
display:block;
font-size:12px;
line-height:18px;
width:180px;
overflow:hidden;
color:{color:Navigation link};
border-bottom:1px solid {color:Wide sidebar background};
padding:5px;
text-align:center;
}
 
#navigationin a:hover{
box-shadow: inset 180px 0 0 0 {color:Wide sidebar background};
color:{color:Hover};
-webkit-transition: all .7s ease-in-out;
-moz-transition: all .7s  ease-in-out;
-o-transition: all .7s  ease-in-out;
transition: all .7s  ease-in-out;
}

#navigationin a{
-webkit-transition: all .7s ease-in-out;
-moz-transition: all .7s  ease-in-out;
-o-transition: all .7s  ease-in-out;
transition: all .7s  ease-in-out;
}

<link href="//maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css" rel="stylesheet"/>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="navi"> NAVIGATION 
  <i class="fa fa-chevron-down"></i>
</div>
 

<div id="navigation">
  <ul>
    <li>menu</li>
    <li>menu</li>
    <li>menu</li>
  </ul>
</div>
 
<div id="navigationin"></div>

Answered By - Spring