Background: I have prepared a form in HTML Service in Google apps script which I call with DoGet function from Code.gs.
my doget function
function doGet() {
r
A jQuery dialog will suit your needs. It is an overlay to the current window - not a "pop up".
The demo code here can be easily adapted to Google Apps Script. Here it is, with much of the extra bits removed:
function doGet() {
var template = HtmlService
.createTemplateFromFile('ModalForm');
var htmlOutput = template.evaluate()
.setSandboxMode(HtmlService.SandboxMode.NATIVE)
.setTitle('jQuery UI Dialog - Modal form');
return htmlOutput;
}