jQuery snippet: Show or hide another element from select option, on change.

show-or-hid-el-from-select-option.css

#foo-other { display: none; }

show-or-hid-el-from-select-option.html

<select name="foo" id="foo-1">
	<option selected value="">Choose …</option>
	<option value="Baz">Baz</option>
	<option value="Bar">Bar</option>
	<option value="Other" data-other="foo-other">Other …</option>
</select>
<div id="foo-other">…</div>

show-or-hid-el-from-select-option.js

$(function() {
	
	'use strict';
	
	// Show or hide another div based on option selected:
	$('select').on('change', function() {
		
		var $this = $(this);
		var key = 'other';
		var $data = $this.data(key);
		var $selected = $this.find(':selected');
		var other = $selected.attr('data-' + key);
		var $temp;
		
		if (other) {
			
			$temp = $('#' + $selected.data(key))
			
			$this.data(key, $temp);
			
			$temp.show();
			
		} else if ($data) {
			
			$data.hide();
			
			$this.removeData('key')
			
		}
		
	});
	
});