How to get optgroup value from Javascript?
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<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;html&gt;
&lt;body&gt;

&lt;select name="lstparameters"&gt;
  &lt;optgroup value="100" label="Swedish Cars"&gt;
    &lt;option value="volvo"&gt;Volvo&lt;/option&gt;
    &lt;option value="saab"&gt;Saab&lt;/option&gt;
  &lt;/optgroup&gt;
  &lt;optgroup value="101" label="German Cars"&gt;
    &lt;option value="mercedes"&gt;Mercedes&lt;/option&gt;
    &lt;option value="audi"&gt;Audi&lt;/option&gt;
  &lt;/optgroup&gt;
&lt;/select&gt;
 
&lt;/body&gt;
&lt;/html&gt;</code></pre>
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<p>How to get optgroup values from javascript?I want to get 100 and 101 values.</p>