title: Bokeh div widget, change the text by pressing a button
body: <p>I want a bokeh button to change the text in a div widget.</p>
  
  <p>I found something similar:</p>
  
  <p><a href="https://groups.google.com/a/continuum.io/forum/#!topic/bokeh/" rel="nofollow noreferrer">https://groups.google.com/a/continuum.io/forum/#!topic/bokeh/</a></p>
  
  <p>I tried to make this fit for my situation, as the example shown in the link was meant to change the text of the button itself: </p>
  
  <pre><code>from bokeh.models import CustomJS
  from bokeh.layouts import row, column
  from bokeh.models.widgets import Div, Button
  
  op="FirstText"
  
  Output= Div(text="""&lt;font size="4"&gt;""" + op + """&lt;/font&gt;""", width=200, height=20)
  
  
  ChangeTextScript = """
      o1="NewText";
      //location.reload();
  """
  
  ResponseButton = Button(label="ChangeText",callback=CustomJS(args={'o1':op},code=ChangeTextScript))
  
  layout=(
      column(
          ResponseButton,
          Output
      )
  )
  
  output_file("ChangeText.html", title="NewText")
  
  show(layout)
  </code></pre>
  
  <p>The button and the "FirstText" are getting displayed, but clicking the button does not change the text. I already found out that the java script is triggered by adding the currently commented line in java script (the page is refreshed when I clicked the button).</p>
  
  <p>I also thought that I could use a "<code>ColumnDataSource</code>" which is used for refreshing Diagrams, but Div does not support "<code>source=...</code>".</p>