案例代码
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<input type="text" id="username"> <br>
<input type="checkbox" name="" id="remember"> 记住用户名
<script>
var username = document.querySelector('#username');
var remember = document.querySelector('#remember');
if (localStorage.getItem('username')) {
username.value = localStorage.getItem('username');
remember.checked = true;
}
remember.addEventListener('change', function() {
if (this.checked) {
if (username.value == '') {
alert('请先填写用户名...');
this.checked = false;
return false;
}
localStorage.setItem('username', username.value);
} else {
localStorage.removeItem('username');
}
})
</script>
</body>
</html>