init_textbox = function($input, settings_element) {
			var i, n, values, option;
	
			var data_raw = $input.attr(attr_data);
	
			if (!data_raw) {
				var value = $.trim($input.val() || '');
				if (!settings.allowEmptyOption && !value.length) return;
				values = value.split(settings.delimiter);
				for (i = 0, n = values.length; i < n; i++) {
					option = {};
					option[field_label] = values[i];
					option[field_value] = values[i];
					settings_element.options.push(option);
				}
				settings_element.items = values;
			} else {
				settings_element.options = JSON.parse(data_raw);
				for (i = 0, n = settings_element.options.length; i < n; i++) {
					settings_element.items.push(settings_element.options[i][field_value]);
				}
			}
		}
Initializes selectize from a <input type="text"> element.

@param {object} $input
@param {object} settings_element