How to use html optgroup tag

##HTML tag definition and usage instructions

tags are often used to group related options together.

If there are many option combinations, you can use the tag to easily group related options together.

The tag is used to group the options provided by the element. When working with a long list of options, grouping related options makes processing easier.

##Example,

by grouping options that are turned off first

<select> 
  <optgroup label="Swedish Cars"> 
    <option value="volvo">Volvo</option> 
    <option value="saab">Saab</option> 
  </optgroup> 
  <optgroup label="German Cars"> 
    <option value="mercedes">Mercedes</option> 
    <option value="audi">Audi</option> 
  </optgroup> 
</select>

Differences between HTML 4.01 and HTML5

none.

Attributes

Global attributes

tag supports global attributes , see the complete property table of HTML global properties.

Event attributes

tag supports all HTML event attributes.

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