function Mod10(ccNumb) {  // v2.0
	var valid = "0123456789"  				// Valid digits in a credit card number
	var len = ccNumb.length;  				// The length of the submitted cc number
	var iCCN = parseInt(ccNumb);  			// integer of ccNumb
	var sCCN = ccNumb.toString();  			// string of ccNumb
	sCCN = sCCN.replace (/^\s+|\s+$/g,'');  // strip spaces
	var iTotal = 0;  						// integer total set at zero
	var bNum = true;  						// by default assume it is a number
	var bResult = false;  					// by default assume it is NOT a valid cc
	var temp;  								// temp variable for parsing string
	var calc;  								// used for calculation of each digit

	// Determine if the ccNumb is in fact all numbers
	for (var j=0; j<len; j++) {
  		temp = "" + sCCN.substring(j, j+1);
  		if (valid.indexOf(temp) == "-1"){
  			bNum = false;
  		}
	}

	// if it is NOT a number, you can either alert to the fact, or just pass a failure
	if(!bNum){
  		/*alert("Not a Number");*/bResult = false;
	}

	// Determine if it is the proper length 
	if((len == 0)&&(bResult)){  				// nothing, field is blank AND passed above # check
  		bResult = false;
	} else{  									// ccNumb is a number and the proper length - let's see if it is a valid card number
  		if(len >= 15){  						// 15 or 16 for Amex or V/MC
    		for(var i=len;i>0;i--){  			// LOOP throught the digits of the card
      			calc = parseInt(iCCN) % 10;  	// right most digit
      			calc = parseInt(calc);  		// assure it is an integer
      			iTotal += calc;  				// running total of the card number as we loop - Do Nothing to first digit
      			i--;  							// decrement the count - move to the next digit in the card
      			iCCN = iCCN / 10;               // subtracts right most digit from ccNumb
      			calc = parseInt(iCCN) % 10 ;    // NEXT right most digit
      			calc = calc *2;                 // multiply the digit by two
      			// Instead of some screwy method of converting 16 to a string and then parsing 1 and 6 and then adding them to make 7,
      			// I use a simple switch statement to change the value of calc2 to 7 if 16 is the multiple.
      			switch(calc){
        			case 10: calc = 1; break;       //5*2=10 & 1+0 = 1
        			case 12: calc = 3; break;       //6*2=12 & 1+2 = 3
        			case 14: calc = 5; break;       //7*2=14 & 1+4 = 5
        			case 16: calc = 7; break;       //8*2=16 & 1+6 = 7
        			case 18: calc = 9; break;       //9*2=18 & 1+8 = 9
        			default: calc = calc;           //4*2= 8 &   8 = 8  -same for all lower numbers
      			}                                               
    			iCCN = iCCN / 10;  				// subtracts right most digit from ccNum
    			iTotal += calc;  				// running total of the card number as we loop
  			}  									// END OF LOOP
  			if ((iTotal%10)==0){  				// check to see if the sum Mod 10 is zero
    			bResult = true;  				// This IS (or could be) a valid credit card number.
  			} else {
    			bResult = false;  				// This could NOT be a valid credit card number
    		}
  		}
	}
	// change alert to on-page display or other indication as needed.
	if(bResult) {
  		//alert("This IS a valid Credit Card Number!");
	}
	if(!bResult){
  		alert("This is NOT a valid Credit Card Number!\nPlease check the number and try again.");
	}
  	return bResult; // Return the results
}