2024-05-29 event.preventDefault()

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event.preventDefault(); // 防止表單提交

2024-05-29 今天學到了 event.preventDefault(); // 防止表單提交

防止秀出系統 default 的訊息 ，使用preventDefault()的medhod()
部份程式如下:

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<button class="submit" type="submit" onclick="btn_submit(event)">註冊

    <div class="toast-success">
        ✅ 註冊成功！可以查看 Email 確認細節！
    </div>

</button>
 
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function btn_submit(event) {
    event.preventDefault(); // 防止表單提交

    let valid = true;

    // 驗證暱稱
    let nickname = document.querySelector('#nick-name').value.trim();
    if (nickname === "" || nickname === null | nickname.length>40) {
        let elem_err_nickname = document.querySelector('.err-nick-name');
        elem_err_nickname.style.visibility = 'visible';
        valid = false;
    } else {
        let elem_err_nickname = document.querySelector('.err-nick-name');
        elem_err_nickname.style.visibility = 'hidden';
    }

    // 驗證電子郵件
    let email = document.querySelector('#email').value.trim();
    if (email === "" || !email.includes('@')) {
        let elem_err_email = document.querySelector('.err-email');
        elem_err_email.style.visibility = 'visible';
        valid = false;
    } else {
        let elem_err_email = document.querySelector('.err-email');
        elem_err_email.style.visibility = 'hidden';
    }

    // 驗證密碼
    let password = document.querySelector('#current-password').value.trim();
    if (password === "" || password.length < 8 || password.length > 100) {
        let elem_err_password = document.querySelector('.err-password');
        elem_err_password.style.visibility = 'visible';
        valid = false;
    } else {
        let elem_err_password = document.querySelector('.err-password');
        elem_err_password.style.visibility = 'hidden';
    }

    // 如果所有字段都有效，允許表單提交
    if (valid) {
                // 清空所有输入字段
                document.querySelector('#nick-name').value = '';
                document.querySelector('#email').value = '';
                document.querySelector('#current-password').value = '';
                document.querySelector('.toast-success').style.display='block'; //show 出註冊成功的訊息
        
    }
    else{
                document.querySelector('.toast-success').style.display='none';
    }
}