Convert a 15 Character SalesForce ID to 18 Character ID

SalesForceID_15_to_18

// Source: https://developer.salesforce.com/forums/ForumsMain?id=906F00000009BWRIA2
var id=prompt('Enter a 15 char ID:','');
id = id.replace(/\"/g, '');
if (id.length != 15) {
  alert('Not 15 Characters');
} else {
  var suffix = '';
  for (var i = 0; i < 3; i++) {
    var flags = 0;
    for (var j = 0; j < 5; j++) {
      var c = id.charAt(i * 5 + j);
      if (c >= 'A' && c <= 'Z') {
        flags += 1 << j;
      }
    }
    if (flags <= 25) {
     suffix += "ABCDEFGHIJKLMNOPQRSTUVWXYZ".charAt(flags);
    } else {
     suffix += '012345'.charAt(flags-26);
    }
  }
  prompt(id+' converts to:',id+suffix);
}