properties.js

function setModalElementByClass(class_name, inner_html) {
  var element = document.getElementsByClassName(class_name)[0]

  if (element) {
    element.innerHTML = inner_html;
  } else {
    console.log('Missing modal element class: ' + class_name)
  }
}

function sendContentToModalListener(funct) {
  return function() {
    funct(this.dataset);
  }
}

function sendImageToModal(content) {
  setModalElementByClass('modal-title', '<a target="_blank" href=' + content.title + '>' + content.title + '</a>');
  setModalElementByClass('modal-body', '<img src=' + content.url + ' height="100%" width="100%"><img>');
  setModalElementByClass('modal-table', "<table class='table'>" + content.content + "</table>");
}

function addOnClickListenersByClass(class_name, funct) {
  var elements = document.getElementsByClassName(class_name);

  if (elements.length) {
    for(i = 0; i < elements.length; i++) {
      elements[i].addEventListener('click', funct)
    }
  }
}

document.addEventListener(
  'DOMContentLoaded',
  addOnClickListenersByClass('thumbnail property-image', sendContentToModalListener(sendImageToModal))
);