September 2022
Intermediate to advanced
585 pages
8h 17m
Chinese
Content preview from JavaScript 经典实例：第三版
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
数据持久化
｜
385
elem.onchange = processField;
}
});
为
localStorage
分配的存储容量因浏览器而异，基本上在
5MB
到
10MB
之间。你
可以使用
try/catch
块测试，确保没有超出用户浏览器的容量限制。
try
{
localStorage.setItem('key', 'value');
}
catch
(domException) {
if
(
['QuotaExceededError', 'NS_ERROR_DOM_QUOTA_REACHED'].includes(
domException.name
)
) {
//
处理超出容量限制错误
}
else
{
//
处理其他错误
}
}
localStorage
对象可离线使用。对上述例程中的表单来说，你可以把数据存储在
localStorage
中，提供一个按钮让用户在联网之后点击，把
localStorage
中
的数
据同步到服务器端存储器中。
14.3.4
参考
Storage
对象，以及
sessionStorage
和
localStorage
对象的进一步说明见
14.2
节。
14.4
使用
IndexedDB
在客户端持久存储大段数
据
14.4.1
问题
你需要更加复杂的客户端数据存储器，其他持久存储方法（例如
localStorage
）无
法胜任。
386
｜
第
14
章
14.4.2
方案
在现代浏览器中，使用
IndexedDB
。
例程
14-3
中的
JavaScript
文件使用
IndexedDB
创建一个数据库和一个数据对象。然 ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.