title: Flask: redirect(url_for()) returning html but not loading page
body: <p>I am building a small web app in Flask, a code excerpt is below. Basically, I am trying to store some data in <code>startsession</code> and then move on to <code>tagpage</code> once this is achieved. But <code>redirect</code> is not working. </p>
  
  <p>When I run <code>TEST 1</code>, it displays <code>hello, world</code> in the console but the main page looks the same.<br>
  When I run <code>TEST 2</code>, it displays the html in the console but the main page looks the same. </p>
  
  <p>Here is what I have:</p>
  
  <pre><code>@app.route('/startsession', methods=['POST'])
  def startsession(): 
      _username = request.form['inputName']
      session['user_name'] = _username    
      ...
      return  redirect(url_for('tagpage')) 
  </code></pre>
  
  <p>Then, either:</p>
  
  <pre><code>### TEST 1
  @app.route("/tagpage")
  def tagpage():
      return "hello, world"
  </code></pre>
  
  <p>Or:</p>
  
  <pre><code>### TEST 2
  @app.route("/tagpage")
  def tagpage():
      return render_template('tagpage.html', filename=filename)
  </code></pre>
  
  <p>Sample of what I see after clicking the button that triggers <code>startsession</code>:</p>
  
  <p><a href="https://i.stack.imgur.com/osw36.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/osw36.png" alt="enter image description here"></a></p>
  
  <p>How can I get the browser to actually go to <code>http://localhost:5000/tagpage</code>?</p>
  
  <p>UPDATE:
  Here is my JQuery script:    </p>
  
  <pre><code>$(function(){
      $("#btnStartSession").click(function(){     
          $.ajax({
              url: '/startsession',
              type: 'POST',
              data: $('form').serialize(),
              success: function(response){
                  console.log(response);
              },
              error: function(error){
                  console.log(error);
              }
          });             
  
  
      });
  });
  </code></pre>