// Credit Card Validation Javascript

function validateCreditCard(s) {
	function cardval(s) {
		// remove non-numerics
		var v = "0123456789";
		var w = "";
		for (i=0; i < s.length; i++) {
		x = s.charAt(i);
		if (v.indexOf(x,0) != -1)
		w += x;
	}
	// validate number
	j = w.length / 2;
	if (j < 6.5 || j > 8 || j == 7) return false;
	k = Math.floor(j);
	m = Math.ceil(j) - k;
	c = 0;
	for (i=0; i<k; i++) {
		a = w.charAt(i*2+m) * 2;
		c += a > 9 ? Math.floor(a/10 + a%10) : a;
	}
	for (i=0; i<k+m; i++) c += w.charAt(i*2+1-m) * 1;
	return (c%10 == 0);
}
}


function isCreditCard(textObj) {
 /*
  *  This function validates a credit card entry.
  *  If the checksum is ok, the function returns true.
  */
   var ccNum;
   var odd = 1;
   var even = 2;
   var calcCard = 0;
   var calcs = 0;
   var ccNum2 = "";
   var aChar = '';
   var cc;
   var r;
   
   ccNum = textObj.value;
   for(var i = 0; i != ccNum.length; i++) {
      aChar = ccNum.substring(i,i+1);
      if(aChar == '-') {
         continue;
      }

      ccNum2 = ccNum2 + aChar;
   }
   
   cc = parseInt(ccNum2);
   if(cc == 0) {
      return false;
   }
   r = ccNum.length / 2;
   if(ccNum.length - (parseInt(r)*2) == 0) {
      odd = 2;
      even = 1;
   }
   
   for(var x = ccNum.length - 1; x > 0; x--) {
      r = x / 2;
      if(r < 1) {
         r++;
      }
      if(x - (parseInt(r) * 2) != 0) {
         calcs = (parseInt(ccNum.charAt(x - 1))) * odd;
      }
      else {
         calcs = (parseInt(ccNum.charAt(x - 1))) * even;
      }
      if(calcs >= 10) {
         calcs = calcs - 10 + 1;
      }
      calcCard = calcCard + calcs;
   }
   
   calcs = 10 - (calcCard % 10);
   if(calcs == 10) {
      calcs = 0;
   }
   
   if(calcs == (parseInt(ccNum.charAt(ccNum.length - 1)))) {
      return true;
   }
   else {
		alert("Invalid credit card number!");
		//textObj.focus();
		errmsg="yes"
		//return errmsg;
      //return false;
   		//document.theform.ccnum.focus();
   }
}