function makeid(length) {
    var result           = [];
    var characters       = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    var charactersLength = characters.length;
    for ( var i = 0; i < length; i++ ) {
      result.push(characters.charAt(Math.floor(Math.random() * 
 charactersLength)));
   }
   return result.join('');
}

console.log(makeid(5));