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Open External Links as Blank Targets via Unobtrusive JavaScript

Beginning with this article, I am serving up a short series of unobtrusive JavaScript functions that I use to enhance the functionality of Perishable Press. In this post, I present a comprehensive JavaScript method of opening external links in new windows (or tabs, depending on the browser).

Blank Targets

One way of opening links in new windows is to insert the HTML target="_blank" attribute into all necessary anchor elements (<a href=""></a>). This method works well, but generates validation errors when used with XHTML-Strict doctypes. Here is an example for those who may be unfamiliar with the good ’ol blank-target attribute:

<a target="_blank" href="https://m0n.co/">Opens in new tab</a>

JavaScript Way

A better solution is to employ some unobtrusive JavaScript to progressively enhance your documents with “blank-target” functionality. Using the following code, 99% of your visitors (those with JavaScript) will enjoy external links opening in new windows, while the remaining 1% of your audience (those without JavaScript) will enjoy your site without even realizing they are missing out on those wonderful blank-targeted links. It’s a “win-win” situation ;)

To implement this unobtrusive, gracefully degradable strategy, simply replace any target="_blank" attributes with the XHTML-friendly rel="external" attribute. Using rel="external" is standards-compliant and thus completely valid, even for XHTML-Strict and XHTML-1.1 doctypes.

After you have prepared your external link anchors with rel="external" attributes, apply the following JavaScript either inline or externally. No additional editing or markup is required — grab, gulp, & go!

// Open External Links as Blank Targets via Unobtrusive JavaScript
// https://perishablepress.com/press/2007/11/20/open-external-links-as-blank-targets-via-unobtrusive-javascript/

function externalLinks() {
	if (!document.getElementsByTagName) return;
	var anchors = document.getElementsByTagName("a");
	for (var i=0; i<anchors.length; i++) {
		var anchor = anchors[i];
		if (
			anchor.getAttribute("href") && ( 
			anchor.getAttribute("rel") == "external" || 
			anchor.getAttribute("rel") == "external nofollow" || 
			anchor.getAttribute("rel") == "nofollow external" )
			)
		anchor.target = "_blank";
	}
}
window.onload = function() {
	externalLinks();
}

Other JavaScript methods for opening external links in new windows work only if the rel attribute is set to external. However, in many situations, especially when working with WordPress and its myriad plugins, external links are also tagged with additional properties, such as nofollow, for example. The code presented in this article opens all links with any of the following attributes in a new window (click links for demo):

Of course, by modifying and/or emulating the sequence of anchor.getAttribute() expressions, it is relatively (no pun intended) straightforward to trigger blank-target behavior for virtually any rel attribute.

Jeff Starr
About the Author Jeff Starr = Fullstack Developer. Book Author. Teacher. Human Being.
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23 responses
  1. Jeff Starr

    @Erik Vold: That’s great! I tried getting the regular expression to match against attribute values containing additional terms (e.g., microformat tags) located either side of the “external” attribute value. I think it was the blank space throwing me off. Regardless, it is good to see an improved version of the script. I am sure it will benefit the community. Thank you for the work, and thanks for sharing it with us. :)

  2. Where did we put those JavaScript code in our blog?

  3. Jeff Starr

    @Adieska: The simplest way is to place the code in the <head> section of your web page(s), like this:

    <script type="text/javascript">
    <!--//--><![CDATA[//><!--

    JavaScript goes here
    JavaScript goes here

    //--><!]]>
    </script>

    Alternately, you can place the code into an external JavaScript file (named something like, “javascript.js”) and then link to the file in the <head> (or footer) section of your web page(s).

  4. Thanks my bro. It works :D

  5. Good. Here, is an interesting post which discuss the same, along with how to open only specific content links in new window.

    http://praveenbattula.blogspot.....indow.html

  6. If you already have another existing script with a window.onload = function() call, you’ll need to add the externalLinks() call to that window.onload call.

  7. Hello everybody.

    I would like to adapt this to open a “form” in a new window, but a form doesn’t have a “href” anchor. Do you know how i could do this ?

    The form is used to pass some parameters to an URL an= the open that URL in a new window. The usual ‘ works perfect, but is no W3C compliant.

    Thanks.

  8. This code is brilliant!

    This is the only way for Drupal 6. I tried many other scripts and they doesn’t work. Great job!

  9. meelijane May 3, 2012 @ 9:48 pm

    @greyliar, there’s a module called ‘external links’ that works just fine.

  10. what if i don’t have rel="..." ?

  11. Thanks for this!
    outline: 0; /* stops the outline on the page over a link! */

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