function ValidateCC(CCType, CCNum)
 {        
        var cctype= document.getElementById(CCType);                                                
//        var ccnum= document.getElementById(CCNum);
       
        var validCCNum=false;
        var validCC=false;
        
        if(CCNum == "")
        {      
            return true;   
        }
        
        validCC= isValidCreditCard(cctype.options[cctype.selectedIndex].text,CCNum);
        if(validCC)
        {  
            return true;                             
        }                               
        else
        {
//            ccnum.focus();
//            ccnum.value = "";
            return false;    
        }                                                                                                            
 }

function isValidCreditCard(type, ccnum) 
{                                        
        if (type == "Visa")                                                
           var re = /^[4]([0-9]{15}$|[0-9]{12}$)/;                    
        else if (type == "MasterCard")                                                    
           var re = /^[5][1-5][0-9]{14}$/;                        
        else if (type == "Discover")                                                   
           var re = /^6011-?\d{4}-?\d{4}-?\d{4}$/;
        else if (type == "Diners Club") 
           var re = /(^30[0-5][0-9]{11}$)|(^(36|38)[0-9]{12}$)/;
        else if (type == "American Express")
            var re = /^3[4,7]\d{13}$/;
        else if (type == "enRoute") 
           var re = /^(2014|2149)[0-9]{11}$/;                        
        else if (type == "JCB") 
           var re = /(^3[0-9]{15}$)|(^(2131|1800)[0-9]{11}$)/;
        else
        {
           alert("Please select credit card type.");
           return false;
        }                              
        if (!re.test(ccnum)) 
        {
           alert("Please enter valid credit card entry.");
           return false;
        }
        ccnum = ccnum.split("-").join("");
                   
        var checksum = 0;
        for (var i=(2-(ccnum.length % 2)); i<=ccnum.length; i+=2) 
        {
             checksum += parseInt(ccnum.charAt(i-1));                           
        }
                   
        for (var i=(ccnum.length % 2) + 1; i<ccnum.length; i+=2)
        {
               var digit = parseInt(ccnum.charAt(i-1)) * 2;
               if (digit < 10) 
                 { checksum += digit; } 
               else 
                 { checksum += (digit-9);}
        }
        if ((checksum % 10) == 0)
        {                           
            return true;
        }
        else 
        {
            alert("Please enter valid credit card entry.");
            return false;
        }
}