optgroup

When showing option elements in select elements, user agents should show the option elements of such groups as being related to each other and separate from other option elements.

<SELECT>
 <OPTGROUP LABEL="Alkaline Metals">
 <OPTION>Lithium (Li)</OPTION>
 <OPTION>Sodium (Na)</OPTION>
 <OPTION>Potassium (K)</OPTION>
 </OPTGROUP>
 <OPTGROUP LABEL="Halogens">
 <OPTION>Fluorine (F)</OPTION>
 <OPTION>Chlorine (Cl)</OPTION>
 <OPTION>Bromine (Br)</OPTION>
 </OPTGROUP> 
</SELECT>
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