记录输入框本地记录用户名效果

<input type="text" id="username">
<input type="checkbox" id="remember">记住用户名

	var username = document.querySelector('#username');
        var remember = document.querySelector('#remember');
        // 判断本地存储有username记录，将值传给输入框，让checkbox状态为true
        if (localStorage.getItem('username')) {
            username.value = localStorage.getItem('username');
            remember.checked = 'true';
        }
        // checkbox变化
        remember.addEventListener('change', function() {
            if (this.checked) {
                // 设置属性
                localStorage.setItem('username', username.value)
            } else {
                // 取消勾选，移除username
                localStorage.removeItem('username');
            }
        })