Validation using Javascript Login Form

How to validation using java script

<html lang="en"> <head> <title>Validation Form using Javascript</title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"> <style> .error{ color: red; font-weight: 600; } </style>  <script> function validationn(){ if(document.forms["frm"]["email"].value==""){ document.forms["frm"]["email"].focus(); document.getElementById("eml").innerHTML="* Enter your Email"; return false; }else{ document.getElementById("eml").innerHTML=""; } /*==========[password]==========*/ if(document.forms["frm"]["pass"].value==""){ document.forms["frm"]["pass"].focus(); document.getElementById("pw").innerHTML="* Enter your Password"; return false; }else{ document.getElementById("pw").innerHTML=""; } } </script> </head> <body> <br> <div class="container"> <div class="row"> <div class=" col-sm-offset-4 col-sm-4"> <div class="panel-group"> <div class="panel panel-default"> <div class="panel-heading text-center"><strong>Login Form Validation</strong></div> <div class="panel-body"> <form class="form-horizontal" action="#" name="frm" onsubmit="return validationn()"> <div class="form-group"> <div class="col-sm-12"> <input type="email" class="form-control" placeholder="Enter your Email" name="email"> <span id="eml" class="error"></span> </div> </div> <div class="form-group"> <div class="col-sm-12"> <input type="password" class="form-control" placeholder="Enter your Password" name="pass"> <span id="pw" class="error"></span> </div> </div> <div class="form-group"> <div class=" col-sm-12"> <button type="submit" class="btn btn-success btn-block">Submit</button> </div> </div> </form> </div> </div> </div> </div> </div> </div> </body> </html>