Function not executing in google script HTML service

Question

I am coding a tool for myself and my classmates that will create a google doc and email it to the selected teacher, using all fields that are filled in and filling all those

Answer 1

In short, customDoc() is a server function and you need to use google.script.run to tell Apps Script to run a specific server function. So instead of calling onclick="customDoc(this.id)", try onclick="google.script.run.customDoc(this.id)". Don't include Code.gs in your HTML file as that's server-side code and it won't work. I highly recommend reading the Client-to-Server Communication guide.

Your customDoc() function is another story :) Below is a very simple way to reorganize your different presets (e.g. subjects) using objects. I also replaced your date formatting code with Utilities.formatDate(), which may be a little easier to comprehend.

function doGet() {
  return HtmlService.createHtmlOutputFromFile('Index.html');
}

function customDoc(subject) {
  var subjects = {
    'math': {
      email: 'teacher@example.com',
      preSubject: 'math for '
    },
    'la': {
      email: 'teacher@example.com',
      preSubject: 'la for '
    },
    'science': {
      email: 'teacher@example.com',
      preSubject: 'science for '
    },
    'is': {
      email: 'teacher@example.com',
      preSubject: 'I&S for '
    },
    'spanish': {
      email: 'teacher@example.com',
      preSubject: 'Español para '
    }
  };

  var formattedDate = Utilities.formatDate(new Date(), Session.getScriptTimeZone(), 'M/d/yyyy');
  
  console.log('Today: ' + formattedDate);
  console.log('Subject: ' + subject);
  console.log(subjects[subject]);
}

  
    
CREATE DOC
    
Email
    
    
    
Doc name
    
    
    
Subject
    
    
    
message
    

    
Fill blanks for subject:

    LA
    Science
    Individuals and societies
    Spanish
    math
  

Try running the above and clicking the science button. You should get an execution log like:

Today: 10/30/2020
Subject: science
{preSubject=science for , email=teacher@example.com}

Now that customDoc() is actually executing, you can start trying to fix the Google Doc generation. It seems to me that you're creating a completely blank Google Doc, which probably isn't what you want. I think you need to work on it some more and then come back if you have more specific questions about generating the document. Good luck!