gistfile1.txt

<h2>target="_blank"なし</h2>
<a href="javascript:alert(document.domain)">なし(javascript:)</a>
<a href="data:text/html,<script>alert(document.domain)</script>">>なし(data:)</a>
<br/>
<h2>target="_blank"あり</h2>
<a href="javascript:alert(document.domain)" target="_blank">あり(javascript:)</a>
<a href="data:text/html,<script>alert(document.domain)</script>" target="_blank">あり(data:)</a>
<h2>target="test"</h2>
<a href="javascript:alert(document.domain)" target="test">あり(javascript:)</a>
<a href="data:text/html,<script>alert(document.domain)</script>" target="test">あり(data:)</a>
<h2>target="ifr"</h2>
<a href="javascript:alert(document.domain)" target="ifr">あり(javascript:)</a>
<a href="data:text/html,<script>alert(document.domain)</script>" target="ifr">あり(data:)</a>
<iframe src="/test.php" name="ifr"></iframe>

<h2>target="ifr2"</h2>
<a href="javascript:alert(document.domain)" target="ifr2">あり(javascript:)</a>
<a href="data:text/html,<script>alert(document.domain)</script>" target="ifr2">あり(data:)</a>
<iframe src="https://example.com" name="ifr2"></iframe>