tablist-js.html

<script>

<!-- when page loads run the iniitalization code -->
  if( document.readyState !== 'loading' ) {
    console.log( 'document is already ready, just execute code here' );
    myInitCode();
  } else {
    document.addEventListener('DOMContentLoaded', function () {
    console.log( 'document was not ready, place code here' );
    myInitCode();
  });
  }
  
function myInitCode() {
  document.getElementById("btn-close").addEventListener("click",closeIt);
  document.getElementById("btn-message").addEventListener("click",aMessage);
  document.getElementById("btn-authorize").addEventListener("click",getSum);
}
//'pick' is a "factory" send the function that you want to run with the args in an array...
function aMessage(){
  google.script.run
      .withSuccessHandler(onSuccess)
      .withFailureHandler(showError)
      .pick('callLibrary');
}

function getSum(){
  google.script.run
      .withSuccessHandler(onSuccess)
      .withFailureHandler(showError)
      .pick('test',[45,55]);
}

function onSuccess(theText){
  document.getElementById('result').innerHTML = theText;
}
  
function showError(err){
  console.log(err);
  document.getElementById('result').innerHTML = "The error is " + err;
}

function closeIt(){
  google.script.host.close();
} 
</script>