# https://www.w3.org/TR/html5/infrastructure.html#floating-point-numbers
# with the addition that a leading '+' sign is ok.
if ( !preg_match( '/^((\+|\-)?\d+(\.\d+)?(E(\+|\-)?\d+)?)?$/i', $value ) ) {
# https://www.w3.org/TR/html5/infrastructure.html#floating-point-numbers
# with the addition that a leading '+' sign is ok.
if ( !preg_match( '/^((\+|\-)?\d+(\.\d+)?(E(\+|\-)?\d+)?)?$/i', $value ) ) {