我怎样才能让innerHtml 只写一次错误？

Question

我有一个问题，我在 javascript 中进行了表单验证，经过所有验证检查后，我输入了innerHtml += "actually error message"，问题是我点击提交按钮多少次它会写出消息。有人可以帮我解决这个问题吗？或者使这个更优雅或更好的逻辑。我是初学者。

function regvalidate() {

  var errortable = document.getElementById('log');

  var x = document.forms["regform"]["username"].value;
  var y = document.forms["regform"]["email"].value;
  var z = document.forms["regform"]["pass1"].value;
  var b = document.forms["regform"]["pass2"].value;

  if (x == "" || y == "" || z == "" || b == "") {
    errortable.innerHTML = 'Cant be empty field';
    return false;
  }

  var regexEmail = /\w+([-+.']\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)*/;
  var email = document.getElementById("email");

  if (regexEmail.test(email.value)) {} else {
    errortable.innerHTML += 'Invaild email address';
    return false;

  }

  password1 = regform.pass1.value;
  password2 = regform.pass2.value;

  if (password1 != password2) {
    errortable.innerHTML += 'Two pass dosent match';
    return false;

  }
}

<div id="log"></div>
<form id="regform" class="form-signin" action="#" method="post">

  <input type="text" id="username" class="form-control" placeholder="username" name="username">

  <input type="email" id="email" class="form-control" placeholder="email" name="email">

  <input type="password" id="pass1" class="form-control" placeholder="password" name="password_1">

  <input type="password" id="pass2" class="form-control" placeholder="password again" name="password_2">
  </br>

  <button class="btn btn-lg btn-primary btn-block" type="submit" onClick="return regvalidate()" name="register_btn">Register</button>

</form>

Answer 1

只需删除=之前的+，如下所示

errortable.innerHTML += 'Two pass dosent match';

或者这样做

errortable.innerHTML = '';
errortable.innerHTML += 'Two pass dosent match';