Detailed introduction to webstorage [local data processing of html5]-H5 Tutorial-php.cn

Home

Web Front-end

H5 Tutorial

Detailed introduction to webstorage [local data processing of html5]

黄舟

Mar 14, 2017 pm 03:51 PM

html5

The editor below will bring you an in-depth analysis of local data processing of webstorage[html5]. The editor thinks it is quite good, so I will share it with you now and give it as a reference for everyone. Come and take a look with the editor, I wish you all a happy game

1. What is webStorage?

webStorage is a method used for localized storage in html5. Before, we used the cookie storage method;

2. What is the difference between them?

Ⅰ. Problems with cookies:

ⅰ. Cookie needs to send a request to the server, and the server returns a cookieId, which is stored in the browser cache requires a certain amount of bandwidth. [Cookies will be sent together with the header information of each HTTP request, which invisibly increases network traffic];

ⅱ. The data capacity stored by cookies is limited and varies depending on the browser type. IE6 can only store approximately 2K;

Ⅱ. And webstorage only needs to store data locally;

3. We can give a small example to illustrate

eg: Enter the user name and password, click button 1 to save the data, click button 2, and you can get it after refreshing the page;

Process:

ⅰ. Create an event

XML/HTML Code复制内容到剪贴板
function MyClick1()   
{   
}

##ⅱ. Get its user name through an id

##JavaScript CodeCopy content to clipboard

var username = $("#TxtUserName").val();

JavaScript Code

Copy content to clipboard

var pwd = $("#TxtPwd").val();

session

Storege, used in Firefox2+火狐 browser;

Life cycle

: The data stored in this way is only valid at the window level. When the same window (or Tab) page is refreshed or jumped, the locally stored data can be obtained. When new When opening a window or page, the original data becomes invalid [current page only]Disadvantages: IE does not support it and cannot achieve persistent data storage.

##JavaScript Code

Copy content to clipboard

sessionStorage.setItem(
"k_username"
, username);            sessionStorage.setItem(
"k_pwd"
, pwd);

Note: sessionStorage.setItem is stored in key-value pairs;

## ②. The second way: localStorage

Detailed introduction to webstorage [local data processing of html5] localStorage It is part of the Web Storage Internet Storage specification and is now supported in Firefox 3.5, Safari 4 and IE8.

Life cycle: Stored in the local C drive, it will still exist after the browser is closed and opened;

Disadvantages: Lower version browsers do not support it.

JavaScript Code复制内容到剪贴板
localStorage.setItem("k_username", username);   
           localStorage.setItem("k_pwd",pwd);

JavaScript Code复制内容到剪贴板
alert("保存成功！");

# #ⅵ.Button 2 prints all the above data

JavaScript Code复制内容到剪贴板
function MyClick2() {   
                alert(sessionStorage.getItem("k_username"));   
                alert(sessionStorage.getItem("k_pwd"));   
            }

The second way to print

JavaScript Code复制内容到剪贴板
function MyClick2() {   
            alert(localStorage.getItem("k_username"));   
            alert(localStorage.getItem("k_pwd"))   
           }

##The result shows:

ⅶ. Extension: removeItem method of localStorage

Detailed introduction to webstorage [local data processing of html5]

//如果我想删除它的用户名怎么做呢？通过它的key把它删除,这样获取时就为空

//localStorage.removeItem("k_username");

Detailed introduction to webstorage [local data processing of html5]

Track local data:

Result display:

Detailed introduction to webstorage [local data processing of html5]

ⅷ.localStorage的clear方法

//如果我想把所有数据都清除？localStorage有个方法

localStorage.clear();

结果显示:

Detailed introduction to webstorage [local data processing of html5]

代码显示：

XML/HTML Code复制内容到剪贴板




    
    
    
    


    
        
            用户名:
            
                
            
        
        
            密码:

4.webStorage制作简易留言板[代码为了展示效果所以把js就直接在html里面写]

XML/HTML Code复制内容到剪贴板
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
    <title></title>
    <script src="js/jquery-1.4.1.min.js"></script>
    <script type="text/javascript">
    $(function () {   
        //4.页面刷新之后判断它是否为空？   
        if (localStorage.getItem("k_showCon") != null) {   
            //5.存在，就把获取到的内容存到里面去   
            "k_showCon", $("#showCon").html(localStorage.getItem("k_showCon"));   
        }   
    });   
        function preservationClick()   
        {   
            var sCon = $("#mCon").val();   
            //2.获取到内容之后加到显示p里去？怎么放呢？这里我们用append方法   
            $("#showCon").append("<p>" + sCon + "</p>");   
            //3.预期的是刷新之后留言还在   
            localStorage.setItem("k_showCon", $("#showCon").html());   
        }   
        function ClearClick()   
        {   
            //6.获取到显示p里面的内容清除   
            $("#showCon").html("");   
            localStorage.clear();   
        }   
    </script>
</head>
<body>
    <p>
        <table>
            <tr>
                <td colspan="2">
                    <textarea id="mCon" cols="25" rows="10"></textarea>
                </td>
            </tr>
            <tr>
                <td><input type="button" value="留言" onclick="preservationClick()" /></td>
                <td><input type="button" value="清除" onclick="ClearClick()" /></td>
            </tr>
        </table>
        <p id="showCon"></p>
    </p>
</body>
</html>

效果显示:

Detailed introduction to webstorage [local data processing of html5]

The above is the detailed content of Detailed introduction to webstorage [local data processing of html5]. For more information, please follow other related articles on the PHP Chinese website!

Statement

The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Understanding H5: The Meaning and SignificanceMay 11, 2025 am 12:19 AM

H5 is HTML5, the fifth version of HTML. HTML5 improves the expressiveness and interactivity of web pages, introduces new features such as semantic tags, multimedia support, offline storage and Canvas drawing, and promotes the development of Web technology.

H5: Accessibility and Web Standards ComplianceMay 10, 2025 am 12:21 AM

Accessibility and compliance with network standards are essential to the website. 1) Accessibility ensures that all users have equal access to the website, 2) Network standards follow to improve accessibility and consistency of the website, 3) Accessibility requires the use of semantic HTML, keyboard navigation, color contrast and alternative text, 4) Following these principles is not only a moral and legal requirement, but also amplifying user base.

What is the H5 tag in HTML?May 09, 2025 am 12:11 AM

The H5 tag in HTML is a fifth-level title that is used to tag smaller titles or sub-titles. 1) The H5 tag helps refine content hierarchy and improve readability and SEO. 2) Combined with CSS, you can customize the style to enhance the visual effect. 3) Use H5 tags reasonably to avoid abuse and ensure the logical content structure.

H5 Code: A Beginner's Guide to Web StructureMay 08, 2025 am 12:15 AM

The methods of building a website in HTML5 include: 1. Use semantic tags to define the web page structure, such as, , etc.; 2. Embed multimedia content, use and tags; 3. Apply advanced functions such as form verification and local storage. Through these steps, you can create a modern web page with clear structure and rich features.

H5 Code Structure: Organizing Content for ReadabilityMay 07, 2025 am 12:06 AM

A reasonable H5 code structure allows the page to stand out among a lot of content. 1) Use semantic labels such as, etc. to organize content to make the structure clear. 2) Control the rendering effect of pages on different devices through CSS layout such as Flexbox or Grid. 3) Implement responsive design to ensure that the page adapts to different screen sizes.

H5 vs. Older HTML Versions: A ComparisonMay 06, 2025 am 12:09 AM

The main differences between HTML5 (H5) and older versions of HTML include: 1) H5 introduces semantic tags, 2) supports multimedia content, and 3) provides offline storage functions. H5 enhances the functionality and expressiveness of web pages through new tags and APIs, such as and tags, improving user experience and SEO effects, but need to pay attention to compatibility issues.

H5 vs. HTML5: Clarifying the Terminology and RelationshipMay 05, 2025 am 12:02 AM

The difference between H5 and HTML5 is: 1) HTML5 is a web page standard that defines structure and content; 2) H5 is a mobile web application based on HTML5, suitable for rapid development and marketing.

HTML5 Features: The Core of H5May 04, 2025 am 12:05 AM

The core features of HTML5 include semantic tags, multimedia support, form enhancement, offline storage and local storage. 1. Semantic tags such as, improve code readability and SEO effect. 2. Multimedia support simplifies the process of embedding media content through and tags. 3. Form Enhancement introduces new input types and verification properties, simplifying form development. 4. Offline storage and local storage improve web page performance and user experience through ApplicationCache and localStorage.

See all articles