Jquery autocomplete dropdown and select id with php and codeigniter

Few days ago I was implementing a drop-down/combo-box for selecting from a huge data, So thought to use jquery autocomplete plugin. But I was very upset while looking for the autocomplete use so that I can select the id to post, I did not find any good resource or documentation about this, I searched over internet and got some post but not what I am looking for. I just wanted to implement the autocomplete for a textbox and after selecting a value I’ll get the id of the value to post. We will discuss on this topic today