需要登录页面的密码和用户名验证

Question

我有一个登录页面，我已经输入了脚本来检查空的用户名和密码，现在想要将密码输入的类别更改为“has-error”，如果输入的数据也是如此用户输入错误，即如果用户输入的用户名不存在于我的数据库中，则用户名字段必须显示错误，如果密码错误，则密码字段必须显示错误。我是我用于我的页面的php和bootstrap的新手 javascript代码是             

<!-- Bootstrap Core JavaScript -->
<script src="../bower_components/bootstrap/dist/js/bootstrap.min.js"></script>

<!-- Metis Menu Plugin JavaScript -->
<script src="../bower_components/metisMenu/dist/metisMenu.min.js"></script>

<!-- Custom Theme JavaScript -->
<script src="../dist/js/sb-admin-2.js"></script>
<script src="../dist/js/formValidation.min.js"></script>
<script src="../dist/js/formValidation.js"></script>
<script type="text/javascript">
function validateText(id)
{
    if($("#"+id).val()==null || $("#"+id).val()=="")
    {
        var div = $("#"+id).closest("div");
        div.addClass("has-error");
        return false;
    }
    else
    {
        var div = $("#"+id).closest("div");
        div.removeClass("has-error");
        return true;
        }
}

$(document).ready(function()
 {
    $("#custbtn").click(function()
    {
        if(!validateText("cusername"))
        {       
            return false;               
            }
        if(!validateText("cpassword"))
        {
            return false;               
            }
        $("form#loginfom").submit();
        });
});
</script>

页面代码为：

<div class="row">
  <div class=" col-lg-offset-3 col-lg-3">
    <div class=" login-panel panel panel-default">
      <div class="panel-heading">
        <h3 class="panel-title text-center">Customer Login</h3>
      </div>
      <div class=" panel-body">
        <form role="form" id="loginfom" action="../Connections/Logincust.php" method="post">
          <fieldset>
            <div class="form-group">
              <input class="form-control" placeholder="Username" id="cusername" name="cusername" type="username" autofocus>
            </div>
            <div class="form-group">
              <input class="form-control" placeholder="Password" id="cpassword" name="cpassword" type="password" value="" autofocus>
            </div>

            <div class="checkbox">
              <label>
                <input name="remember" type="checkbox" value="Remember Me">Remember Me
              </label>
            </div>
            <!-- Change this to a button or input when using this as a form -->

            <button type="button" id="custbtn" class="btn btn-primary btn-lg btn-block"> Login </button>
          </fieldset>
        </form>
      </div>
    </div>
  </div>
</div>

logincust.php的代码