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Basic

Use select2() function on select element to convert it to Select 2.

Nested

Add options inside the optgroups to for group options.

Placeholder

Apply Placeholder by setting option placeholder option.

Tagging with multi-value select boxes

Set tags: true to convert select 2 in Tag mode.

Small Select2

Use data('select2') function to get container of select2.

Disabling options

Disable Select using disabled attribute.

Limiting the number of Tagging

Set maximumSelectionLength: 2 with tags: true to limit selectin in Tag mode.