41 lines
921 B
JavaScript
41 lines
921 B
JavaScript
// https://jqueryvalidation.org/creditcard-method/
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// based on https://en.wikipedia.org/wiki/Luhn_algorithm
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$.validator.addMethod( "creditcard", function( value, element ) {
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if ( this.optional( element ) ) {
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return "dependency-mismatch";
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}
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// Accept only spaces, digits and dashes
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if ( /[^0-9 \-]+/.test( value ) ) {
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return false;
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}
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var nCheck = 0,
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nDigit = 0,
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bEven = false,
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n, cDigit;
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value = value.replace( /\D/g, "" );
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// Basing min and max length on
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// https://developer.ean.com/general_info/Valid_Credit_Card_Types
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if ( value.length < 13 || value.length > 19 ) {
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return false;
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}
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for ( n = value.length - 1; n >= 0; n-- ) {
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cDigit = value.charAt( n );
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nDigit = parseInt( cDigit, 10 );
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if ( bEven ) {
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if ( ( nDigit *= 2 ) > 9 ) {
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nDigit -= 9;
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}
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}
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nCheck += nDigit;
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bEven = !bEven;
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}
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return ( nCheck % 10 ) === 0;
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}, "Please enter a valid credit card number." );
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