javascript，HTML，PHP，ASP做301跳转代码 SEO优化设置

URL HTTP Redirection

URL http redirection is an automatic URL change operation from one URL to another URL.

• URL redirect
  • Server side redirect
  • Client side redirect
  • HTTP status codes
  • HTTP 301 redirect
• Redirect options
  • PHP redirect
  • Apache .htaccess redirect
  • ASP redirect
  • ASP.NET redirect
  • Meta refresh redirect
  • Javascript redirect
  • jQuery redirect
  • Canonical link redirect
  • Frame redirect
  Redirect code generator

URL redirection

URL page redirection is an automatic URL change operation from one URL to another URL.

This redirection is done for the following reasons:

1. Redirect from old obsolete URL to a new updated URL.
2. Redirect from old obsolete domain to a new domain.
3. Redirect from non www domain name to a www domain name.
4. Redirect from short URL name to a long URL name - URL shortening service.
5. URL shortening service will allow the user to insert a short URL and be redirected the the long URL that has the real page contents.

The user may reach the old URL from an old external links or a bookmark.

by the site's webmaster who adds a script.

Server side redirect

Server side redirection is done in the server, by configuring the Apache / IIS server software or by using PHP / ASP / ASP.NET script.

This is the preferred way to redirect URLs, since you can return HTTP 301 Moved Permanently status code.

Search engines use the 301 status to transfer the page rank from the old URL to the new URL.

Client side redirect

Client side redirection is done in the web browser of the user, by using HTML meta refresh tag or by Javascript code.

Client redirect is less preferred, since it does not return HTTP 301 status code.

Where to put redirect code

Domain name	Hosting server	Redirect code placement
not changed	not changed	old page on same server
not changed	changed	old page on new server
changed	not changed	old page on same server
changed	changed	old page on old server

* Only with .htaccess redirect: add redirect code to httpd.conf file or to .htaccess file.

HTTP status codes

Status code	Status code name	Description
200	OK	successful HTTP request
300	Multiple Choices
301	Moved Permanently	permanent URL redirection
302	Found	temporary URL redirection
303	See Other
304	Not Modified
305	Use Proxy
307	Temporary Redirect
404	Not Found	URL not found

HTTP 301 redirect

HTTP 301 Moved Permanently status code means a permanent URL redirection.

The 301 redirect is the preferred way to redirect URLs, since it informs search engines that the URL has moved for good, and search engines should put the new URL page in the search results instead of the old URL page and transfer the new URL page, the page rank of the old URL page.

The 301 redirect can be done across domains or on the same domain.

Google recommends to use 301 redirect.

Redirect options

Redirect script	Redirect side	Old page file type	Redirect URL or domain	Old URL server type	301 redirect support
PHP	Server-side	.php	URL	Apache / Linux	yes
ASP	Server-side	.asp	URL	IIS / Windows	yes
ASP.NET	Server-side	.aspx	URL	IIS / Windows	yes
.htaccess	Server-side	all	URL / Domain	Apache / Linux	yes
IIS	Server-side	all	URL / Domain	IIS / Windows	yes
HTML canonical link tag	Client-side	.html	URL	all	no
HTML meta refresh	Client-side	.html	URL	all	no
HTML frame	Client-side	.html	URL	all	no
Javascript	Client-side	.html	URL	all	no
jQuery	Client-side	.html	URL	all	no

redirect script - the scripting language that is used for the redirection.

redirect side - where the redirection takes place - server-side or client-side.

old page file type - the type of the old URL page that can can contain the scripting language of the redirect code.

redirect URL or domain - does support URL redirection of a single web page or domain redirection of a whole website.

typical old URL server type - the typical software and operating system of the server.

301 redirect support - indicates whether permanent 301 redirect status response can be returned.

PHP redirect

Replace old-page.php code with redirection code to new-page.php.

old_page.php:

<?php
// PHP permanent URL redirection
header("Location: http://www.mydomain.com/new-page.php", true, 301);
exit();
?>

The old page must have .php file extension.

The new page can be with any extension.

See: PHP redirect

Apache .htaccess redirect

.htaccess file is a local configuration file of the Apache server.

If you have permission the change the httpd.conf file, it is better to add the Redirect directive in thehttpd.conf instead of the .htaccess file.

Single URL redirect

Permanent redirect from old-page.html to new-page.html.

.htaccess:

Redirect 301 /old-page.html http://www.mydomain.com/new-page.html

Entire domain redirect

Permanent redirect from all domain pages to newdomain.com.

 .htaccess file should be at the old website's root directory.

.htaccess:

Redirect 301 / http://www.newdomain.com/

See: .htaccess redirection

ASP redirect

old-page.asp:

<%@ Language="VBScript" %>
<%
' ASP permanent URL redirection
Response.Status="301 Moved Permanently"
Response.AddHeader "Location", "http://www.mydomain.com/new-page.html"
Response.End
%>

ASP.NET redirect

old-page.aspx:

<script language="C#" runat="server">
// ASP.net permanent URL redirection
private void Page_Load(object sender, EventArgs e)
{
   Response.Status = "301 Moved Permanently";
   Response.AddHeader("Location","http://www.mydomain.com/new-page.html");
   Response.End();
}
</script>

HTML meta refresh redirect

HTML meta refresh tag redirection does not return 301 permanent redirect status code, but considered by Google as a 301 redirect.

Replace old page with redirection code with the URL of the page you want to redirect to.

old-page.html:

<!-- HTML meta refresh URL redirection -->
<html>
<head>
   <meta http-equiv="refresh" 
   content="0; url=http://www.mydomain.com/new-page.html">
</head>
<body>
   <p>The page has moved to:
   <a href="http://www.mydomain.com/new-page.html">this page</a></p>
</body>
</html>

See: HTML redirection

Javascript redirect

Javascript redirect does not return 301 permanent redirect status code.

Replace old page with redirection code with the URL of the page you want to redirect to.

old-page.html:

<html>
<body>
<script type="text/javascript">
    // Javascript URL redirection
    window.location.replace("http://www.mydomain.com/new-page.html");
</script>
</body>
</html>

See: Javascript redirection

jQuery redirect

jQuery redirect is actually another type of Javascript redirect.

jQuery redirect does not return 301 permanent redirect status code.

Replace old page with redirection code with the URL of the page you want to redirect to.

old-page.html:

<!DOCTYPE html>
<html>
<body>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.2/jquery.min.js"></script>
<script type="text/javascript">
   // jQuery URL redirection
   $(document).ready( function() {
      url = "http://www.mydomain.com/new-page.html";
      $( location ).attr("href", url);
  });
</script>
</body>
</html>

See: jQuery redirection

HTML canonical link tag redirect

The canonical link does not redirect to the preffred URL, but it can be an alternative to URL redirection for websites that most of the traffic arrives from search engines.

HTML canonical link tag can be used when there are several pages with similar content and you want to tell the search engines which page you preffer to use in the search results.

Canonical link tag can link to the same domain and also cross-domain.

Add the canonical link tag to the old page to link to the new page.

Add the canonical link tag to the pages that you preffer not to get search engines traffic to link to the preffered page.

The canonical link tag should be added in the <head> section.

old-page.html:

<link rel="canonical" href="http://www.mydomain.com/new-page.html">

See: Canonical URL link

HTML frame redirect

In frame redirection the new-page.html file is viewed by an html frame.

This is not a real URL redirection.

Frame redirection is not search engines friendly and is not recommended.

old-page.html:

<!-- HTML frame redirection -->
<html>
<head>
    <title>Title of new page</title>
</head>
<frameset cols="100%">
    <frame src="http://www.mydomain.com/new-page.html">
    <noframes>
     <a href="http://www.mydomain.com/new-page.html">Link to new page</a>
    </noframes>
</frameset>
</html>