<!--
var CCtype = {"34":"AMEX","37":"AMEX","51":"MASTERCARD","52":"MASTERCARD","53":"MASTERCARD","54":"MASTERCARD","55":"MASTERCARD","60":"DISCOVER"};

function mod10( cardNumber ) { // LUHN Formula for validation of credit card numbers.
	var ar = new Array( cardNumber.length );
	var i = 0,sum = 0;


    	for( i = 0; i < cardNumber.length; ++i ) {
    		ar[i] = parseInt(cardNumber.charAt(i));
    	}
    	for( i = ar.length -2; i >= 0; i-=2 ) { // you have to start from the right, and work back.
    		ar[i] *= 2;							 // every second digit starting with the right most (check digit)
    		if( ar[i] > 9 ) ar[i]-=9;			 // will be doubled, and summed with the skipped digits.
    	}										 // if the double digit is > 9, ADD those individual digits together 


        	for( i = 0; i < ar.length; ++i ) {
        		sum += ar[i];						 // if the sum is divisible by 10 mod10 succeeds
        	}
        	return (((sum%10)==0)?true:false);	 	
    }

		    

        function expired( month, year ) {
        	var now = new Date();							// this function is designed to be Y2K compliant.
        	var expiresIn = new Date(year,month,0,0,0);		// create an expired on date object with valid thru expiration date
        	//expiresIn.setMonth(expiresIn.getMonth()+1);		// adjust the month, to first day, hour, minute & second of expired month
					//alert(expiresIn);
        	if( now.getTime() < expiresIn.getTime() ) return false;
        	return true;									// then we get the miliseconds, and do a long integer comparison
    }


        function validateCCard(cardNumber) {
        	if( cardNumber.length == 0 ) {						//most of these checks are self explanitory
        		alert("Please enter a valid card number.");
						document.theform.cardnumber.focus();
        		return false;				
        	}
        	for( var i = 0; i < cardNumber.length; ++i ) {		// make sure the number is all digits.. (by design)
        		var c = cardNumber.charAt(i);


            		if( c < '0' || c > '9' ) {
            			alert("Please enter a valid card number. Use only digits. do not use spaces or hyphens.");
            			return false;
            		}
            	}
            	var length = cardNumber.length;			//perform card specific length and prefix tests
                 var prefix = parseInt( cardNumber.substring(0,1));
								 if(prefix==4){
								    cardType="VISA";
								 }else{
								    var cardprefix = parseInt( cardNumber.substring(0,2));
								    var cardType = CCtype[cardprefix];
								  }
									
								// alert(cardType);

                	switch( cardType ) {
                		case 'AMEX':


                    			if( length != 15 ) {
                    				alert("Please enter a valid American Express Card number. Must has 15 digits.");
														document.theform.cardnumber.focus();
                    				return false;
                    			}
                    			var prefix = parseInt( cardNumber.substring(0,2));


                        			if( prefix != 34 && prefix != 37 ) {
                        				alert("Please enter a valid American Express Card number.");
																document.theform.cardnumber.focus();
                        				return false;
                        			}
                        			break;
                        		case 'DISCOVER':


                            			if( length != 16 ) {
                            				alert("Please enter a valid Discover Card number. Must has 16 digits.");
																		document.theform.cardnumber.focus();
                            				return false;
                            			}
                            			var prefix = parseInt( cardNumber.substring(0,4));


                                			if( prefix != 6011 ) {
                                				alert("Please enter a valid Discover Card number.");
																				document.theform.cardnumber.focus();
                                				return false;
                                			}
                                			break;
                                		case 'MASTERCARD':


                                    			if( length != 16 ) {
                                    				alert("Please enter a valid MasterCard number.  Must have 16 digits without spaces or hyphens.");
																						document.theform.cardnumber.focus();
                                    				return false;
                                    			}
                                    			var prefix = parseInt( cardNumber.substring(0,2));


                                        			if( prefix < 51 || prefix > 55) {
                                        				alert("Please enter a valid MasterCard number. ");
																								document.theform.cardnumber.focus();
                                        				return false;
                                        			}
                                        			break;
																							
                                        		case 'VISA':


                                            			if( length != 16 ) {
                                            				alert("Please enter a valid Visa Card number. Must have 16 digits.");
																										document.theform.cardnumber.focus();
                                            				return false;
                                            			}
                                            			var prefix = parseInt( cardNumber.substring(0,1));


                                                			if( prefix != 4 ) {
                                                				alert("Please enter a valid Visa Card number.");
																												document.theform.cardnumber.focus();
                                                				return false
                                                			}
                                                			break;
                                                	}
																									
                                                	if( !mod10( cardNumber ) ) { 		// run the check digit algorithm
                                                		alert("Sorry,  this is not a valid credit card number.");
                                                    document.theform.cardnumber.focus();      
																										return false;
                                                	}
																								/*	
                                                	if( expired( cardMonth, cardYear ) ) {							// check if entered date is already expired.
                                                		alert("Sorry! The expiration date you have entered would make this card invalid.");
                                                		return false;
                                                	}		
																									*/
                                                document.theform.cardtype.value=cardType;
                                                	return true; // at this point card has not been proven to be invalid
     }  // end card validation
	
//-->