How to add a button that jumps to an external link in the content type? I would like to add a purchase button in the content type, the button is an internal link, for example:www.example.com/go/nodeid. And then add an external purchase link to the text field, for example:https://item.jd.com/2385876.html. Click the buy button (internal link) JS jump to the external links, because I do not want to search engine crawling the external link address.
For example,
 open the page（http://www.chong4.com.cn/read.php?18818）, showing the link（http://www.chong4.com.cn/cydb/go.php?18818_127334_22s）, click will jump to（https://detail.tmall.com/item.htm?id=536478627694&amp;ali_trackid=2:mm_13376157_4604749_42838263,22s18818:1479362916_3k2_69258376）
nofollow: Links to an unendorsed document, like a paid link. ("nofollow" is used by Google, to specify that the Google search
  spider should not follow that link)
  
  source: HTML  rel Attribute


All you have to do is write your link like this:

&lt;a rel="nofollow" href="http://www.example.com/something"&gt;Buy Now&lt;/a&gt;