Email Address Validation (Contain char, @ symbol and dot '.') using Java Script

HTML File

  
   
  <div class="lbl">Email : </div>
  <div class="ctrl">
       <input type="text" name="mail" id="mail">
       <span id ="err_mail"></span>
  </div>
  

Java Script File

  
   
function mail_validation(mail)
{
  var mailformat = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
    if (mail.value.match(mailformat))
    {
        document.getElementById("err_mail").innerHTML = "";
        return true;
    }
    else
    {
        var msg = "please enter valid mail addr. ...";
        document.getElementById("err_mail").innerHTML = msg;
        mail.focus();
        return false;
    }  
}