Search field or searchbox for searching in dropdowns

[MOTTU .K.ANAND]

Hi,

I want to add a searchbox in gmail addon which created using google app script. I'm using Cardservice for creating the gmail add-on.Not using HTMLservice(don't know much about that and its usage).In google app script there is selcyion input type for dropdown. I want  a searchbox for searching in dropdown in google app script. How can i add or create searchbox in cardsevice selectioninputtype in google app script?Please anybody anser quickly....