Check if the ISBN number is legal_PHP tutorial

[Program language] PHP [Source code source] http://px.sklar.com [Function description] Check whether the ISBN number entered by the user (with or without hyphens) is legal. The source code is as follows: ＜?php /* * Check to see if the entered isbn is valid and return * true or false depending. * Im not even going to try to claim copyright for such * a simple thing. Do what you will with it . * 8-) Keith Nunn, kapn@anglican.ca */ function checkisbn($isbn) { $isbn10 = ereg_replace("[^0-9X]","",$isbn); $checkdigit = 11 - ( ( 10 * substr($isbn10,0,1) + 9 * substr($isbn10,1,1) + 8 * substr($isbn10,2,1) + 7 * substr($isbn10,3,1) + 6 * substr($isbn10,4,1) + 5 * substr($isbn10,5,1) + 4 * substr($isbn10,6,1) + 3 * substr($isbn10,7,1) + 2 * substr( $isbn10,8,1) ) % 11); if ( $checkdigit == 10 ) $checkdigit = "X"; if ( $checkdigit == 11 ) $checkdigit = 0; if ( $checkdigit == substr($isbn10 ,9,1) ) { return true; } else { return false; } } ?＞

http://www.bkjia.com/PHPjc/532111.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/532111.htmlTechArticle[Programming Language] PHP [Source Code Source] http://px.sklar.com [Function Description] Check User Whether the entered ISBN number (with or without hyphens) is legal. The source code is as follows: ＜?php...