var url = ["http://www.linkedin.com/in/jannuelanarna", "http://www.linkedin.com/in/jannuela", undefined, undefined];

​

var publicUrl = ["http://www.linkedin.com/in/jannuelanarna", "http://www.linkedin.com/pub/jay-r-bautista/64/b29/45b", undefined, "http://www.linkedin.com/pub/ronilo-canson/75/927/4a3", "http://www.linkedin.com/pub/siddharth-chaudhary/33/aa1/8", "http://www.linkedin.com/in/rojohnh", "http://www.linkedin.com/pub/lara-martinez/74/777/a3b", "http://www.linkedin.com/pub/alena-ortega/69/72a/415", "http://www.linkedin.com/in/nivlek1416", "http://www.linkedin.com/pub/emmar-reveriza/59/a91/132", "http://www.linkedin.com/in/samsanchezcb", "http://www.linkedin.com/pub/mitch-stevens/6b/375/3a0", "http://www.linkedin.com/pub/irish-jane-sumadic/29/339/910", "http://www.linkedin.com/pub/joel-sumadic/45/31b/ab3", "http://www.linkedin.com/pub/luna-cielo-yniesta/68/4b2/690"];

​

var value = "http://www.linkedin.com/pub/luna-cielo-yniesta/68/4b2/690";

​

if (arraysHaveDuplicate(value, url, publicUrl)) {

  alert('Found: '+value);  

}

else {

  alert('Not found: '+value); 

}

​

var badValue = "This won't be found!";

if (arraysHaveDuplicate(badValue, url, publicUrl)) {

  alert('Found: '+badValue);  

}

else {

  alert('Not found: '+badValue); 

}

​

function arraysHaveDuplicate(needle, arr1, arr2) {

  //will return first duplicate or false

  for (var i=0; i<arr1.length; ++i) {

    if (arr2.indexOf(needle) !== -1) {

       return arr1[i];

    }

  }

  return false; //no match

}