G201: Giving users advanced warning when opening a new window

The objective of this technique is to provide a warning before automatically opening a new window or tab. Opening new windows automatically when a link is activated can be disorienting for people who have difficulty perceiving visual content, and for some people with cognitive disabilities, if they are not warned in advance. Providing a warning allows the user to decide it they want to leave the current window, and the warning will help them find their way back, if they do decide they would like to go to the new window. It will help them understand that the "back" button will not work and that they have to return to the last window they had open, in order to find their previous location.

Examples

Example 1: Including the warning in the text describing a control

The name or label that describes a control can include the warning about opening in a new window.

Example Code:

<a href="knitting.html" target="_blank">All about Knitting 
  (opens in new window)</a>

Example 2: Using CSS to provide a warning before opening a new window

The code below uses CSS to provide a warning before opening a new window.

Example Code:

<html>
  <head>
    <title>Pop-Up Warning</title>
    <style type="text/css">
    body {
      margin-left:2em;
      margin-right:2em;
    }
    :focus { outline: 0; }
    a.info {
      position:relative;
      z-index:24;
      background-color:#ccc;
      color:#000;
      text-decoration:none
    }
    a.info:hover, a.info:focus, a.info:active {
      z-index:25;
      background-color:#ff0
    }
    a.info span {
      position: absolute;
      left: -9000px;
      width: 0;
      overflow: hidden;
    }
    a.info:hover span, a.info:focus span, a.info:active span {
      display:block;
      position:absolute;
      top:1em; left:1em; width:12em;
      border:1px solid #0cf;
      background-color:#cff;
      color:#000;
      text-align: center
    }
    div.example {
      margin-left: 5em;
    }
  </style>
  </head>
  <body>
    <h1>Pop-Up Warning</h1>
    <p> This is an example of an <a class="info"
        href="popup_advisory_technique.html" target="_blank">
    	 <strong>External link</strong><span>Opens a new
          window</span></a>
    </p>
  </body>
</html>

A working example of Using CSS to provide a warning before opening a new window is available.

Related Techniques

Tests

Procedure

For each link that opens automatically in a new window or tab when a change of context is initiated by a user request:

Check that there is a warning spoken in assistive technology that this link opens to a new window.
Check that there is a visual warning in text that this link opens to a new window.

Expected Results

Checks #1 and check #2 are true.

If this is a sufficient technique for a success criterion, failing this test procedure does not necessarily mean that the success criterion has not been satisfied in some other way, only that this technique has not been successfully implemented and can not be used to claim conformance.