Source

File: wp-admin/includes/template.php

function get_submit_button( $text = '', $type = 'primary large', $name = 'submit', $wrap = true, $other_attributes = '' ) {
	if ( ! is_array( $type ) ) {
		$type = explode( ' ', $type );
	}

	$button_shorthand = array( 'primary', 'small', 'large' );
	$classes          = array( 'button' );

	foreach ( $type as $t ) {
		if ( 'secondary' === $t || 'button-secondary' === $t ) {
			continue;
		}

		$classes[] = in_array( $t, $button_shorthand, true ) ? 'button-' . $t : $t;
	}

	// Remove empty items, remove duplicate items, and finally build a string.
	$class = implode( ' ', array_unique( array_filter( $classes ) ) );

	$text = $text ? $text : __( 'Save Changes' );

	// Default the id attribute to $name unless an id was specifically provided in $other_attributes.
	$id = $name;
	if ( is_array( $other_attributes ) && isset( $other_attributes['id'] ) ) {
		$id = $other_attributes['id'];
		unset( $other_attributes['id'] );
	}

	$attributes = '';
	if ( is_array( $other_attributes ) ) {
		foreach ( $other_attributes as $attribute => $value ) {
			$attributes .= $attribute . '="' . esc_attr( $value ) . '" '; // Trailing space is important.
		}
	} elseif ( ! empty( $other_attributes ) ) { // Attributes provided as a string.
		$attributes = $other_attributes;
	}

	// Don't output empty name and id attributes.
	$name_attr = $name ? ' name="' . esc_attr( $name ) . '"' : '';
	$id_attr   = $id ? ' id="' . esc_attr( $id ) . '"' : '';

	$button  = '<input type="submit"' . $name_attr . $id_attr . ' class="' . esc_attr( $class );
	$button .= '" value="' . esc_attr( $text ) . '" ' . $attributes . ' />';

	if ( $wrap ) {
		$button = '<p class="submit">' . $button . '</p>';
	}

	return $button;
}