title: Verify text field not empty using Selenium WebDriver
body: <p>Suppose I want to verify that a text input field with the ID of "text_input" is not empty (contains text) before continuing to click on a submit button, such as:</p>
  
  <pre><code>// verify that html element id "text_input" is not null
  
  var button_Save = Driver.Instance.FindElement(By.Id("submit"));
  button_Save.Click();
  </code></pre>
  
  <p>How could one go about this?</p>
  
  <p>The HTML for the element I want to verify is not null is:</p>
  
  <pre><code>&lt;input name="text_input" value="Fred" id="text_input" tabindex="6" class="label" type="text"&gt;
  </code></pre>