XHTML Strict does not allow opening links in a new window using target=””_blank”” so instead you can use jQuery to add the target attribute to all <a> tags after the page has loaded and still have the page validate as XHTML strict. (But refer to my updated note at the end of the article regarding the base tag and the un-deprecation of the target attribute).
jQuery Code
Simply add the following piece of code into your $(document).ready(function() { } section of code.
$(""a"").filter(function() {
return this.hostname && this.hostname !== location.hostname;
}).attr('target', '_blank');
What this does is to add target=’_blank’ to all <a> tags in the current webpage that do not link to the domain you are currently on.
Therefore on my blog, applying the jQuery code above would make the following open in the same window:
<a href=""/jquery-open-offsite-links-new-window/""> ... </a> <a href=""https://electrictoolbox.com/jquery-open-offsite-links-new-window/""> ... </a>
and the following in a new window:
<a href=""http://www.google.com""> ... </a> <a href=""http://www.yahoo.com""> ... </a>
It’s then possible to replace attr() with other functions to do things to external links on a page.
Update September 23rd 2011
With HTML5, the W3C has un-deprecated the target attribute so you can add target attributes to <a> and <form> tags and have the document still validate. Using jQuery as shown above can still be useful if you have a lot of pages and don’t wish to have to manually update all the links.