title: generate an auto prefix number in jquery
body: <p><div class="snippet" data-lang="js" data-hide="false" data-console="false">
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  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;select id="questionnaire_domain" class="form-control sync-option-text required" name="questionnaire_domain"&gt;&lt;option value="ESS"&gt;Employee Satisfaction Survey&lt;/option&gt;&lt;option value="CSS"&gt;Customer Satisfaction Survey&lt;/option&gt;&lt;option value="VSS"&gt;Vendor Satisfaction Survey&lt;/option&gt;&lt;option value="OQ"&gt;Orientation Quiz&lt;/option&gt;&lt;option value="TQ"&gt;Training Quiz&lt;/option&gt;&lt;option value="EI"&gt;Exit Interview&lt;/option&gt;&lt;option value="EO"&gt;Employee Opinion&lt;/option&gt;&lt;/select&gt;
  &lt;input class="form-control readonly" name="questionnaire_code" type="text" value="" id="questionnaire_code" readonly=""&gt;</code></pre>
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  <p>I want to generate an auto  prefix number in the text field according to the selected drop down's option value.
  E.g: If I select Exit Interview the auto generated prefix will be 'EI12345',here 'EI' comes from drop down value and '12345' is an auto sequence number.</p>