How do Auto Clomplete open the low of the line where it is being typed?

I have an auto complete system and wanted the options to appear lower than the line where the user is typing, such as code editors such as dreamweaver .

Auto Complete - Jquery:

$(function() {
var availableTags = [
  "<a></a>",
  "<sub></sub>"
];
function split( val ) {
  return val.split( /\s*/ );
}
function extractLast( term ) {
  return split( term ).pop();
}

$( "#tags" )
  // don't navigate away from the field on tab when selecting an item
  .bind( "keydown", function( event ) {
    if ( event.keyCode === $.ui.keyCode.TAB &&
        $( this ).autocomplete( "instance" ).menu.active ) {
      event.preventDefault();
    }
  })
  .autocomplete({
    minLength: 0,
    source: function( request, response ) {
      // delegate back to autocomplete, but extract the last term
      response( $.ui.autocomplete.filter(
        availableTags, extractLast( request.term ) ) );
    },
    focus: function() {
      // prevent value inserted on focus
      return false;
    },
    select: function( event, ui ) {
      var terms = split( this.value );
      // remove the current input
      terms.pop();
      // add the selected item
      terms.push( ui.item.value );
      // add placeholder to get the comma-and-space at the end
      terms.push( "" );
      this.value = terms.join( "" );
      return false;
    }
  });

});

HTML:

<textarea id="tags" ></textarea>