JSFiddle - React, Tailwind, and code Playground

by SengKook Park

HTML

<ul>
  <li><a href="http://google.com">http://google.com</a></li>
  <li><a href="/tutorial">/tutorial.html</a></li>
  <li>
   <a href="ftp://ftp.com/file.zip">ftp://ftp.com/file.zip</a>
  </li>
  <li><a href="http://nodejs.org">http://nodejs.org</a></li>
</ul>

CSS

.external { background-color: yellow }

JavaScript

var aArr = document.getElementsByTagName("a");
for(var index in aArr) {
    // alert(aArr[index].getAttribute("href"));
    if(isExternal(aArr[index].getAttribute("href"))) {
        aArr[index].className = "external";
    }
}
    
function isExternal(url) {
    var protocol = location.protocol;
    var host = location.host;
    if(url.indexOf("/")==0 || ~ url.indexOf(protocol+"://"+host)) {
      return false;
    } else {
      return true;
    }
}