没有表单的Html 5表单验证

Question

能否实现html5表单验证

<form>
    <input type="email" id="email" placeholder="Enter your email here..." required>
    <button type="submit">Submit</button>
</form>

可以不用Form吗

<div>
    <input type="email" id="email" placeholder="Enter your email here..." required>
    <button type="submit">Submit</button>
</div>

Answer 1

是的，使用约束验证 API。参见 http://www.w3.org/TR/html5/forms.html#the-constraint-validation-api .例如，您可以调用 element 。检查有效性()。另见 https://developer.mozilla.org/en-US/docs/Web/Guide/HTML/HTML5/Constraint_validation或 https://developer.mozilla.org/en-US/docs/Web/API/HTMLSelectElement/checkValidity .例如:

var email = document.getElementById('email');
var valid = email . checkValidity();
if (!valid) ...

或者使用在 checkValidity() 失败时触发的 invalid 事件:

email.addEventListener("invalid", function() { alert("Email invalid"); });

您可以使用setCustomValidity 来设置有效性状态和/或错误消息:

if (!email.value) email.setCustomValidity("Email is missing");