Which code should i use for search popup like here

Well i use costume menu but i can't make search popup window like here i try this code "<a href='/search' onclick="showhide(document.getElementById('search_menu')); return false;">Pretraga</a></li>" but it's not works

Here is how it looks im not editing it in redirection url im editing it in overall_header

Not working nothing shows when i click on Pretraga button after editing.

i've purchase from him.

That code doesn't exist in overal_header

That was in index body, remove it but still the same.