Modify external link attributes
You can determine whether external links open in the same tab/window or in a new tab/window by using the target attribute in the HTML reference tag. When the attribute value is _BLANK the linked site opens in a new tab. When the attribute value is _TOP the linked site opens in the same tab.
For example:
<a href="http://google.com" rel="external" target="_blank">LINK _BLANK</a>
opens in a new tab.
<a href="http://google.com" rel="external" target="_top">LINK _TOP</a>
opens in the same tab.