Change all domains in links on a website - php

Question

need some advice on how to fix an ugly situation. our forum has resided on a couple of different domains over the years. we lost one domain that was in use 5-6 yrs ago and apparently some posts on our forum still have links in the threads that point to the old domain. what would be the most efficient way to change all links that point to
http://www.olddomain.com/stuff
point to
http://www.newdomain.com/stuff
the only part that has changed is the domain name, all thread variables in the url remain the same. is this something that is best done client side with javascript/jquery or should it be handled on a server level with a PHP function (dont know where to begin here..)? some pseudocode that doesn't seem to do what I need it to on the client side...
$('a').each(function() {
var domanin = 'newdomain';
if(href.search('olddomain.com') != -1) {
$(this).attr('href', newdomain);
}
});
thank you

Answer 1

I think it will make more sense if you handle this in the back end. Search engines will not notice the change you make through JavaScript.
So I advise you search for those domains in your database and replace them there.

Answer 2

Well you should probably do this on the server side, as it was said before, but if you can't for whatever reason, here is what you could do on the javascript side of things.
$('a').each(function() {
this.host = 'www.newdomain.com';
});
Note that this example uses jQuery, but you could do the same in plain javascript with getElementsByTagName.

Answer 3

To do this in JavaScript (w/ jQuery):
$('a').each(function() {
var link = this.href;
if(link.search('olddomain.com') != -1) {
this.href = link.replace('olddomain.com', 'newdomain.com');
}
});
Here is a jsfiddle: http://jsfiddle.net/tHXxK/
However I would suggest changing the links in the database, just get rid of all the old references. To do this create a script that searches for the old URLs and replaces them, something like:
$query = mysql_query("SELECT [id], [link] FROM [table] WHERE [link] LIKE '%//olddomain.com/%' OR [link] LIKE '%//www.olddomain.com/%'", $db) or trigger_erroR(mysql_error());
while ($row = mysql_query($query)) {
$iQuery = mysql_query("UPDATE [table] SET [link]='" . mysql_real_escape_string(str_replace(array('//olddomain.com/', '//www.olddomain.com/'), array('//newdomain.com/', '//www.newdomain.com/'), $row['link']) . "' WHERE [id]=" . $row['id']), $db) or trigger_error(mysql_error());
}

Answer 4

If it'd be me, I would have used a server side script to replace all instances of the old domain with the new one and be done with it once and for all.
I assume your forum DB is rather a large one. For the sake of system resources you can write a multi-step script and do the job in multiple steps.
This is a better approach as it can improve the data consistency for search engines as well.