javascript - How to Call Google Apps Script from Web Page

Question

Have searched high and low for this. I have a web page of basic HTML/CSS/JS. I want users to be able to visit the page and upon opening page, a call is made to a google script I made which takes information from a spreadsheet and displays some of it on the page. I am hoping I don't have to do any fancy set up like in Google's tutorials because none of them were helpful to me.

My Webpage ----> Google Script ----> Google Spreadsheet
My Webpage <---- Google Script <---- Google Spreadsheet

Users should be able to select an item shown on the webpage (item populated from spreadsheet) and click a button which will allow users to enter a new page with a URL derived from the selected item.

This is essentially a chat room program where the chat rooms are stored on a spreadsheet. I want users to be able to create a new chat room as well which should update the google spreadsheet.

Answer 1

Look into using the GET parameters. https://stackoverflow.com/a/14736926/2048063.

Here's a previous question on the topic.

You can access the parameters passed by GET in your doGet(e) function using e.parameter. If you call http://script.google......./exec?method=doSomething, then

function doGet(e) {
  Logger.log(e.parameter.method);
}

doSomething will be written to the log, in this case.

Returning data from the script can be done using the ContentService, which allows you to serve JSON (I recommend). JSON is easiest (in my opinion) to make on the GAS end, as well as use on the client end.

The initial "populate list" call would look something like this. I will write it in jQuery because I feel that is very clean.

var SCRIPT_URL = "http://script.google.com/[....PUT YOUR SCRIPT URL HERE....]/exec";
$(document).ready(function() {
    $.getJSON(SCRIPT_URL+"?callback=?",
              {method:"populate_list"},
              function (data) { 
                alert(JSON.stringify(data)); 
              });
});

And the corresponding GAS that produces this.

function doGet(e) {
  if (e.parameter.method=="populate_list") {
    var v = {cat:true,dog:false,meow:[1,2,3,4,5,6,4]}; //could be any value that you want to return
    return ContentService.createTextOutput(e.parameter.callback + "(" + JSON.stringify(v) + ")")
        .setMimeType(ContentService.MimeType.JAVASCRIPT);
  }
}

This method is called JSONP, and it is supported by jQuery. jQuery recognizes it when you put the ?callback=? after your URL. It wraps your output in a callback function, which allows that function to be run on your site with the data as an argument. In this case, the callback function is the one defined in the line that reads function (data) {.