Safari IPAD, how to "simulate" a tap on DropDownList to show options to select?

Here is the scenario, on an Ipad, I have a web page, who has a textbox for search and a drop down list. When you enter some text on the textbox, via jquery and webservices im doing a query search and populating the result into de dropdownlist.

On desktop Safari works fine, because im expanding de drop down's height when it has results to show, but on Ipad doesnt work , to see the result the user must "do a touch" on the DDL and the a "popup" with the option appears. Javascript focus() doesn't work.

What I want to do is after drop down is populated to "force or simulate" a tap on the drop down list, so the user can see the options.