silverstripe-framework/forms/NumericField.php

<?php

/**
 * Text input field with validation for numeric values. Supports validating
 * the numeric value as to the {@link i18n::get_locale()} value.
 *
 * @package forms
 * @subpackage fields-formattedinput
 */
class NumericField extends TextField {

	public function Type() {
		return 'numeric text';
	}

	public function getAttributes() {
		return array_merge(parent::getAttributes(), array(
			'type' => 'number',
			'step' => 'any' // allows entering float/decimal numbers like "1.2" instead of just integers
		));
	}

	public function validate($validator) {
		if(!$this->value && !$validator->fieldIsRequired($this->name)) {
			return true;
		}

		require_once THIRDPARTY_PATH."/Zend/Locale/Format.php";

		$valid = Zend_Locale_Format::isNumber(
			trim($this->value),
			array('locale' => i18n::get_locale())
		);

		if(!$valid) {
			$validator->validationError(
				$this->name,
				_t(
					'NumericField.VALIDATION', "'{value}' is not a number, only numbers can be accepted for this field",
					array('value' => $this->value)
				),
				"validation"
			);

			return false;
		}

		return true;
	}

	public function dataValue() {
		return (is_numeric($this->value)) ? $this->value : 0;
	}
}