can anybody help me settle this thing ? cause i have problem on closing my side menu navigation bar. I only can close the navigation bar when i click on the x mark. but i want to close it when i click outside of the navigation bar. can anybody help me please.. ?
function openNav() {
    document.getElementById("mySidenav").style.width = "250px";
    document.getElementById("hehe").style.marginLeft = "250px";
 document.getElementById("main").style.marginLeft = "250px";
    document.body.style.backgroundColor = "rgba(0,0,0,0.4)";
}
function closeNav() {
    document.getElementById("mySidenav").style.width = "0";
    document.getElementById("hehe").style.marginLeft= "0";
 document.getElementById("main").style.marginLeft = "0";
    document.body.style.backgroundColor = "white";
}
var acc = document.getElementsByClassName("accordion");
var i;
for (i = 0; i < acc.length; i++) {
  acc[i].onclick = function() {
    this.classList.toggle("active");
    var panel = this.nextElementSibling;
    if (panel.style.maxHeight){
      panel.style.maxHeight = null;
    } else {
      panel.style.maxHeight = panel.scrollHeight + "px";
    } 
  }
}body {
    font-family: "Lato", sans-serif;
    transition: background-color .5s;
 background: url(pic/admin2.jpg) no-repeat center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
  overflow:hidden;
}
.sidenav {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: #111;
    overflow-x: hidden;
    transition: 0.5s;
    padding-top: 60px;
}
.sidenav a {
    padding: 8px 8px 8px 32px;
    text-decoration: none;
    color: #818181;
    display: block;
    transition: 0.3s
}
.sidenav a:hover, .offcanvas a:focus{
    color: #7CFC00;
}
.sidenav .closebtn {
    position: absolute;
    top: -10px;
    right: 0px;
    font-size: 50px;
}
#main {
    transition: margin-left .5s;
    padding: 10px;
 position: absolute;
    top: 4px;
    left: 4px;
 position:fixed absolute relative;
 border-radius: 0px 118px 118px 118px;
-moz-border-radius: 0px 118px 118px 118px;
-webkit-border-radius: 0px 118px 118px 118px;
border: 6px solid #818181;
color: #818181;
}
#main:hover
{
 border-radius: 0px 118px 118px 118px;
-moz-border-radius: 0px 118px 118px 118px;
-webkit-border-radius: 0px 118px 118px 118px;
border: 6px solid #7CFC00;
 color: #7CFC00;
}
@media screen and (max-height: 450px) {
  .sidenav {padding-top: 15px;}
  .sidenav a {font-size: 18px;}
}
.lalala {
 position: absolute; 
 bottom: 50px;
 cursor: pointer;
    padding: 18px;
    width: 100%;
    text-align: left;
    border: none;
    outline: none;
    transition: 0.4s; 
}
a.accordion:after {
    content: '\002B';
    color: #777;
    font-weight: bold;
    float: right;
    margin-left: 5px;
}
a.accordion.active:after {
    content: "\2212";
 color: #7CFC00;
}
div.panel {
    padding: 0 25px;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.2s ease-out;
 font-size: 15px;
}
.navbar {
  overflow: hidden;
  background-color: #333;
  position: fixed;
  top: 0;
  width: 100%;
}
.huhu {
    position: relative;
    top: 0px;
    left: 70px;
    font-size: 50px;
 color:#818181;
}
.text {
    position: relative;
    top: 70px;
    left: 100px;
 color:#818181;
}
.head{
 text-decoration: none;
 color:#818181;
}
.head:hover{
 text-decoration: none;
 color:#7CFC00;
}
#hehe{
 transition: margin-left .5s;   
}<!DOCTYPE html>
<html>
<head>
</head>
<body>
<div id="mySidenav" class="sidenav">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">×</a>
  <a href="admin.php" class="focus">Home</a>
  <a href="#" class="accordion">Department</a>
<div class="panel">
  <a href="AdminDepartmentList.php">List of department</a>
  <a href="AdminDepartmentAdd.php">Add department</a>
</div>
<a href="#" class="accordion">User</a>
<div class="panel">
  <a href="AdminUserList.php">List of User</a>  
  <a href="AdminUserAdd.php">Add User</a>
</div>
<a href="#" class="accordion">System & Vendor</a>
<div class="panel">
  <a href="#">List of System</a>
  <a href="#">List of Vendor</a>
  <a href="#">Records</a>
</div>
  <a href="#" >User Log</a>
<div id="lalala" class="lalala">
  <a href="logoutAdmin.php" >Log Out</a>
</div>
</div>
<div id="main">
  <span style="font-size:30px;cursor:pointer" onclick="openNav()">☰</span>
</div>
<div id="hehe">
<div class="huhu">
<a href="admin.php" class="head">
Vendor Records System
</a>
</div>
<div class="text">
Welcome Admin
</div>
</div>
</body>     
</html>  
     
    