function verifyEmail(email){
var status = false;     
var emailRegEx = /^[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$/i;
     if (email.search(emailRegEx) != -1)
     {
          status = true;
     }
     return status;
}

function checkform(mf)
{
  var error='';
  if(mf.name.value=="")
  {
    error=error+" - Name is mandatory field. \n";
  }
  if(mf.email.value=="")
  {
    error=error+" - Email is mandatory field. \n";
  }
  if(mf.email.value!="" && verifyEmail(mf.email.value)==false)
  {
    error=error+" - Wrong email. \n";
  }
  if(mf.message.value=="")
  {
    error=error+" - Message is mandatory field. \n";
  }
  if (error!="")
  {
    alert("Sorry, there are errors:\n"+error);
    return false;
  }
  else
  {
    return true;
  }
}