rheajt/Code.gs

## Code.gs
function onOpen() {
  SpreadsheetApp.getUi()
    .createMenu('MULTI DATA VALIDATION')
    .addItem('Open', 'openSidebar')
    .addToUi();
}

function onInstall() {
  installEditTrigger();
  onOpen();
}

function openSidebar() {
  var html = HtmlService.createHtmlOutputFromFile('Sidebar').setTitle('Multi Data Validation');

  return SpreadsheetApp.getUi().showSidebar(html);
}

/**
 * Used to fill the select field in the sidebar
 */
function getSheets() {
  var sheets = SpreadsheetApp.getActiveSpreadsheet().getSheets();

  var sheetNames = [];
  for(var i = 0; i < sheets.length; i++) {
    sheetNames.push(sheets[i].getName());
  }
  return sheetNames;
}

function getDataVals() {
  var dataVals = PropertiesService.getDocumentProperties().getProperty('DATA_VALS');

  return JSON.parse(dataVals) || {};
}

function setDataVals(dataVals) {
  dataVals = JSON.stringify(dataVals);

  PropertiesService.getDocumentProperties().setProperty('DATA_VALS', dataVals);
}

function installEditTrigger() {
  var sheet = SpreadsheetApp.openById('17c1fQcEiJXRmWhdLJu7MjMfuqw3nVSsus1_jF7SBWPo');
//  var sheet = SpreadsheetApp.getActive();
  ScriptApp.newTrigger('onEdit').forSpreadsheet(sheet).onEdit().create();
}

function onEdit(e) {
  if(e.range.getDataValidation()) {
    var dataVals = getDataVals();

    var column = e.range.getColumn() + 1;
    var row = e.range.getRow();

    var adjCell = columnToLetter(column, row);

    var subCats = dataVals[e.value.toString()];

    var rule = SpreadsheetApp.newDataValidation()
      .requireValueInList(subCats, true)
      .build();

    SpreadsheetApp.getActiveSheet().getRange(adjCell).setDataValidation(rule);
  }
}

//turn numbers into "A1" format for cell value
function columnToLetter(column, row) {
  var temp, letter = '';
  while (column > 0) {
    temp = (column - 1) % 26;
    letter = String.fromCharCode(temp + 65) + letter;
    column = (column - temp - 1) / 26;
  }
  return letter + row;
}

## Sidebar.html
<link rel="stylesheet" href="https://ssl.gstatic.com/docs/script/css/add-ons1.css">

<style>
  label {display: block;}
  section.settings {
    display: none;
  }
</style>

<body class="sidebar">

  <div class="block">

    <button class="action" onclick="show('named-range')">Named Ranges</button>

    <button class="action" onclick="show('multi-column')">Multiple Columns</button>

  </div>

  <section class="settings" id="named-range">

    <div class="block">
      <h1>Named Range Categories</h1>
      <p>This method requires that you manually define the named ranges of your categories.</p>
      <p>Once you have defined your named ranges click create below.</p>
    </div>

    <hr/>

    <div class="block">
      <button class="create" onclick="createDataValidation('named')">Create</button>
    </div>

  </section>

  <section class="settings" id="multi-column">

    <div class="block">
      <h1>Multiple Columns</h1>
      <p>This method takes all of the columns from the sheet you select and creates data validation from them.</p>
      <p>Once you have selected the sheet that contains your categories in separate colums, click create below.</p>
    </div>

    <div class="block">
      <label>Sheet with categories</label>
      <select id="multi-category-sheet"></select>
    </div>

    <hr/>

    <div class="block">
      <button class="create" onclick="createDataValidation('multi')">Create</button>
    </div>

  </section>

</body>


<script>
function main() {
  google.script.run
    .withSuccessHandler(placeSheets)
    .getSheets();
}

function placeSheets(sheets) {
  var multiSheet = document.getElementById('multi-category-sheet');

  for(var i = 0; i < sheets.length; i++) {
    multiSheet.options.add(new Option(sheets[i], sheets[i]));
  }
}


function createDataValidation(type) {

  switch(type) {
    case 'named':

      google.script.run
        .withSuccessHandler(google.script.host.close)
        .namedRangeCategories();

      break;

    case 'multi':
      var sheet = document.getElementById('multi-category-sheet').value;

      google.script.run
        .withSuccessHandler(google.script.host.close)
        .multiColumnCategories(sheet);

      break;

    default: break;
  }


//  google.script.run
//    .withSuccessHandler(google.script.host.close)
//    .createDataValidation(data);
}

/**
 * show the correct inputs
 */
function show(settings) {
  var sections = document.getElementsByClassName('settings');

  for(var i = 0; i < sections.length; i++) {
    sections[i].style.display = 'none';
  }

  document.getElementById(settings).style.display = 'block';
}

window.onload = main;

</script>


## undefined
getMultiCategories
	function onOpen() {
	SpreadsheetApp.getUi()
	.createMenu('MULTI DATA VALIDATION')
	.addItem('Open', 'openSidebar')
	.addToUi();
	}

	function onInstall() {
	installEditTrigger();
	onOpen();
	}

	function openSidebar() {
	var html = HtmlService.createHtmlOutputFromFile('Sidebar').setTitle('Multi Data Validation');

	return SpreadsheetApp.getUi().showSidebar(html);
	}

	/**
	* Used to fill the select field in the sidebar
	*/
	function getSheets() {
	var sheets = SpreadsheetApp.getActiveSpreadsheet().getSheets();

	var sheetNames = [];
	for(var i = 0; i < sheets.length; i++) {
	sheetNames.push(sheets[i].getName());
	}
	return sheetNames;
	}

	function getDataVals() {
	var dataVals = PropertiesService.getDocumentProperties().getProperty('DATA_VALS');

	return JSON.parse(dataVals) \|\| {};
	}

	function setDataVals(dataVals) {
	dataVals = JSON.stringify(dataVals);

	PropertiesService.getDocumentProperties().setProperty('DATA_VALS', dataVals);
	}

	function installEditTrigger() {
	var sheet = SpreadsheetApp.openById('17c1fQcEiJXRmWhdLJu7MjMfuqw3nVSsus1_jF7SBWPo');
	// var sheet = SpreadsheetApp.getActive();
	ScriptApp.newTrigger('onEdit').forSpreadsheet(sheet).onEdit().create();
	}

	function onEdit(e) {
	if(e.range.getDataValidation()) {
	var dataVals = getDataVals();

	var column = e.range.getColumn() + 1;
	var row = e.range.getRow();

	var adjCell = columnToLetter(column, row);

	var subCats = dataVals[e.value.toString()];

	var rule = SpreadsheetApp.newDataValidation()
	.requireValueInList(subCats, true)
	.build();

	SpreadsheetApp.getActiveSheet().getRange(adjCell).setDataValidation(rule);
	}
	}

	//turn numbers into "A1" format for cell value
	function columnToLetter(column, row) {
	var temp, letter = '';
	while (column > 0) {
	temp = (column - 1) % 26;
	letter = String.fromCharCode(temp + 65) + letter;
	column = (column - temp - 1) / 26;
	}
	return letter + row;
	}