title: How to validate HTML dropdown lists and input fields before clicking the submit button using jQuery
body: <p>This is my question: I have three drop-down lists and two input fields. This is my code.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
   &lt;title&gt;&lt;/title&gt;
  &lt;/head&gt;
  &lt;body&gt;
     
    Name : &lt;input type="text" id="one"/&gt;&lt;br/&gt;&lt;br/&gt;&lt;br/&gt;
    &lt;label for="two"&gt;Select category&lt;/label&gt;
     &lt;select id="two"&gt;
      &lt;option&gt;--select--&lt;/option&gt;
      &lt;option&gt;books&lt;/option&gt;
      &lt;option&gt;penss&lt;/option&gt;
      &lt;option&gt;pensils&lt;/option&gt;
      &lt;option&gt;erasers&lt;/option&gt;
     &lt;/select&gt;
   &lt;br/&gt;&lt;br/&gt;&lt;br/&gt;
     &lt;label for="three"&gt;Select country&lt;/label&gt;
      &lt;select id="three"&gt;
      &lt;option&gt;--select--&lt;/option&gt;
      &lt;option&gt;japan&lt;/option&gt;
      &lt;option&gt;canada&lt;/option&gt;
      &lt;option&gt;usa&lt;/option&gt;
      &lt;option&gt;uk&lt;/option&gt;
     &lt;/select&gt;
  &lt;br/&gt;&lt;br/&gt;&lt;br/&gt;
     Amount :&lt;input type="text" id="four"/&gt;
  &lt;br/&gt;&lt;br/&gt;&lt;br/&gt;
      &lt;label for="five"&gt;Select city&lt;/label&gt;
      &lt;select id="five"&gt;
      &lt;option&gt;--select--&lt;/option&gt;
      &lt;option&gt;ottawa&lt;/option&gt;
      &lt;option&gt;washinton&lt;/option&gt;
      &lt;option&gt;austin&lt;/option&gt;
      &lt;option&gt;texas&lt;/option&gt;
     &lt;/select&gt;
  &lt;br/&gt;&lt;br/&gt;&lt;br/&gt;
  &lt;input type="submit"&gt;
  &lt;/body&gt;
  &lt;/html&gt;</code></pre>
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  </div>
  </p>
  
  <p>So what I want is to validate like this,</p>
  
  <p>If the user selects any field (input or section) from any place, not selected fields should be validated. They cannot use the submit button. As an example if the user selects the middle selection (countries) and at that time other fields are not selected all should validate on clicking of the select. How can I do that?</p>