if(!dojo._hasResource["dojox.validate.isbn"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code. dojo._hasResource["dojox.validate.isbn"] = true; dojo.provide("dojox.validate.isbn"); dojox.validate.isValidIsbn = function(/* String */value) { // summary: Vadlidate ISBN-10 or ISBN-13 based on the length of value // returns: Boolean var len, sum, weight; if(typeof value!='string'){ value = String(value); } value = value.replace(/[- ]/g,''); //ignore dashes and whitespaces len = value.length; sum = 0; if(len == 10){ weight = 10; // ISBN-10 validation algorithm for(var i = 0; i< 9; i++){ sum += parseInt(value.charAt(i)) * weight; weight --; } var t = value.charAt(9).toUpperCase(); sum += t == 'X' ? 10 : parseInt(t); return sum % 11 == 0; }else if(len == 13) { weight = -1; for(var i=0; i< len; i++){ sum += parseInt(value.charAt(i)) * (2 + weight); weight *= -1; } return sum % 10 == 0; }else{ return false; } } }