需要用到本地存储localStorage
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<input type="text" id="username"><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){
localStorage.setItem('username',username.value)
}else{
localStorage.removeItem('username');
}
})
</script>
</body>
</html>