index.html

<script>
  System.config({
    transpiler: 'typescript', 
    typescriptOptions: { emitDecoratorMetadata: true }, 
    packages: {'app': {defaultExtension: 'ts'}} 
  });
  System.import('app/main')
        .then(null, console.error.bind(console));
</script>

index2.html

document.write("<button id='mybtn'>Click Me</button>");
var _this = this;
_this.hello = "Hello World";
var btn = document.getElementById('mybtn');
btn.addEventListener('click', function () {
        document.write(_this.hello);
    });