title: Change Dropdown values based on input in textfield
body: <p>I try to find a solution, but I can't find it and I am not able to program it by myself. I hope you can help me.</p>
  
  <p>I have 2 elements: A textfield and a drop down menu (select/options).</p>
  
  <p>Based on the birth/year of a person I enter into the textfield, I want to have a related drop down values.</p>
  
  <p>If the person is 0-17 years old, the values in the drop down should bei 0, 100, 200, 300, 400, 500, 600.
  If the person is 18 years old or older, the values in the drop down should bei 300, 500, 1000, 1500, 2000, 2500.</p>
  
  <p>Example: If I enter 1978 into the text field, the drop down menu should show the values 300, 500,…
  If I enter 2002 into the text field, the drop down menu should show the values 100, 200,…</p>
  
  <p>I hope it is understandable what I am looking for.</p>
  
  <p>I have checked this one:
  <a href="https://stackoverflow.com/questions/15052763/change-dropdown-value-based-on-text-input">Change dropdown value based on Text Input</a></p>
  
  <p>and also this one, which looks also similar to what I need:
  <a href="https://stackoverflow.com/questions/6975517/jquery-change-hidden-value-based-on-input-field?rq=1">jQuery - Change hidden value based on input field</a></p>
  
  <p>But I can't make it. </p>
  
  <p>A jsfiddle would be really cool!</p>
  
  <p>Thank you in advance.</p>
  
  <pre><code> &lt;input name="Year" type="text" value="" /&gt;
  
   &lt;select name="Results"&gt;
   &lt;option selected="selected" value=""&gt;please choose:&lt;/option&gt;
   &lt;option value="300"&gt;300.-&lt;/option&gt;
   &lt;option value="500"&gt;500.-&lt;/option&gt;
   &lt;option value="1000"&gt;1000.-&lt;/option&gt;
   &lt;option value="1500"&gt;1500.-&lt;/option&gt;
   &lt;option value="2000"&gt;2000.-&lt;/option&gt;
   &lt;option value="2500"&gt;2500.-&lt;/option&gt;
   &lt;/select&gt;
  
   &lt;select name="Results"&gt;
   &lt;option selected="selected" value=""&gt;please choose:&lt;/option&gt;
   &lt;option value="100"&gt;100.-&lt;/option&gt;
   &lt;option value="200"&gt;200.-&lt;/option&gt;
   &lt;option value="300"&gt;300.-&lt;/option&gt;
   &lt;option value="400"&gt;400.-&lt;/option&gt;
   &lt;option value="500"&gt;500.-&lt;/option&gt;
   &lt;option value="600“&gt;600.-&lt;/option&gt;
   &lt;/select&gt;
  </code></pre>
  
  <p>Kind regards,
  Andy</p>