title: Angular 2 Material Input change placeholder dynamically
body: <p>I want to change the text of the input placeholder dynamically.
  The console.log already gives the updated string but the interface doesn't update so there stays the old placeholder.
  How can I get the Interface to recognize the change?</p>
  
  <pre><code>document.getElementById(this.implicKey).setAttribute('placeholder', options[i].implication);
  
  console.log(document.getElementById(this.implicKey).getAttribute('placeholder'));
  </code></pre>