1jQuery(document).ready(function() {
  2
  3    var cvvname = "";
  4    if (jQuery("#cccvv").length) {
  5        cvvname = "#cccvv";
  6    } else {
  7        cvvname = "#cardcvv";
  8    }
  9
 10    function isAmex()
 11    {
 12        // Check if AMEX was selected from the dropdown.
 13        var cc = jQuery("#cctype").val();
 14        var ccInfo = jQuery("[name='ccinfo']:checked").val();
 15        if (cc.toLowerCase().indexOf("american express") !== -1) {
 16            return true;
 17        }
 18        if (typeof ccInfo != 'undefined') {
 19            return (ccInfo.toLowerCase() == 'useexisting');
 20        }
 21        return false;
 22    }
 23
 24    function isCardTypeVisible()
 25    {
 26        return jQuery("#ccTypeButton:visible").length > 0;
 27    }
 28
 29    jQuery(cvvname).focus(function() {
 30        if (isAmex() || !isCardTypeVisible()) {
 31            jQuery(cvvname).attr("maxlength", "4");
 32        } else {
 33            jQuery(cvvname).attr("maxlength", "3");
 34        }
 35    });
 36
 37    jQuery("#cctype").change(function() {
 38        var cardcvv = jQuery(cvvname).val();
 39        if (!isAmex() && cardcvv.length > 3) {
 40            // Reset the CVV, since it's too long now.
 41            jQuery(cvvname).val("");
 42        } 
 43    });
 44});
 45
 46