title: Property 'value' does not exist on type 'HTMLElement' for Textarea - Angular
body: <p>Using Angular 4 (typescript), I have the below HTML code:</p>
  
  <pre><code> &lt;div *ngIf="dataService.selected_markers.length == 0" id="tsnPasteContainer"&gt;
        &lt;form style="width: 100%; height: 100%"&gt;
          &lt;textarea id="tsn_list" style="width: 100%; height: 100%" type="text" name="tsn_list" placeholder="e.g. 2001311,2425302,2153542,2435974"&gt;&lt;/textarea&gt;
        &lt;/form&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>I am trying to get the data that the user is typing into the textarea using:</p>
  
  <pre><code>public parseTSNs(){
      let tsnString = document.getElementById("tsn_list").value;
      console.log("User inputted string: " + tsnString);
  }
  </code></pre>
  
  <p>This function is called by a button.</p>
  
  <p>The code is not compiling due to:</p>
  
  <pre><code>Property 'value' does not exist on type 'HTMLElement'
  </code></pre>
  
  <p>This should be a simple function.  What am I doing wrong? W3schools "getting values from textarea" shows '.value' as the required function!</p>