Performs error detection and correction.
// ==UserScript==
// @name Validate Library Card
// @namespace http://mailerdaemon.home.comcast.com/
// @include https://*.libraryreserve.com/*/SignIn*.htm*
// @include https://*.libraryreserve.com/*/LogIn*.htm*
// @version 1.0
// @description Performs error detection and correction.
// ==/UserScript==
const extrasize = 3;
function luhn(str){
if(typeof(str) !== "string")
str = Array.join(str, "");
if((str = str.replace(/\D/g, "")).length) {
var t = [0,2,4,6,8,1,3,5,7,9]
var [valid, concat] = Array.reduce(str, function([b, a], c){ let j = Number(c); return [a + j, b + t[j]];}, [0, 0]);
return [str, !(valid % 10), str.concat(9 - (concat + 9) % 10)];
}
return [str, undefined, "0"];
}
$Z("//input[(@id='card' or @name='LibraryCardNumber') and @type='text']", function(input){
let checksum = document.createElement("span");
insertAfter(checksum, input)
let update = function (e){
let value = input.value.replace(/[\s\-_]/g,'');
let len = value.length;
let num = Number(value);
let check;
if(len && !isNaN(num))
{
if(len < 13){
input.style.backgroundColor = "";
checksum.innerHTML = check = "";
}
else if(len == 13){
checksum.innerHTML = check = luhn(value)[2].slice(-1);
input.style.backgroundColor = "#AFA";
}
else if(len == 14){
var [str, success] = luhn(value);
checksum.innerHTML = ""
check = str.slice(-1);
if(success)
input.style.backgroundColor = "#5F5";
else
input.style.backgroundColor = "#FAA";
}
else
input.style.backgroundColor = "#F00";
//log(value, len, check)
}
//else log(value, "wtf?")
if(input.value.length + extrasize > input.size)
input.size = input.value.length + extrasize;
}
addEvent(input, "keyup", update);
addEvent(input, "change", update);
addEvent(checksum, "click", function(){input.value += checksum.innerHTML; update();});
});
function $Z(_xpath, func, node){
var doc = (node && (typeof(node.ownerDocument) === "object"))?(node.ownerDocument || node):(node = document);
var res = doc.evaluate(_xpath, node, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
var args = Array.prototype.slice.call(arguments, 3);
var i = 0;
for (; i < res.snapshotLength; ++i)
func.apply(func, [res.snapshotItem(i), i].concat(args));
return i;
}
function insertAfter(insert, after){return after.parentNode.insertBefore(insert, after.nextSibling);}
function insertBefore(insert, before){return before.parentNode.insertBefore(insert, before);}
function addEvent( obj, type, fn, capture ) {
if ( obj.attachEvent ) {
obj["e"+type+fn] = fn;
obj[type+fn] = function() { obj["e"+type+fn]( window.event ); }
obj.attachEvent( "on"+type, obj[type+fn] );
} else
obj.addEventListener( type, fn, capture?capture:false );
}
function removeEvent( obj, type, fn, capture ) {
if ( obj.detachEvent ) {
obj.detachEvent( "on"+type, obj[type+fn] );
obj[type+fn] = obj["e"+type+fn] = null;
} else
obj.removeEventListener( type, fn, capture?capture:false );
}
function log(){
var arg;
switch(arguments.length)
{
case 1:
arg = arguments[0];
break;
case 0:
arg = null;
break;
default:
arg = arguments;
break;
}
var f = arg//JSON.stringify(arg);
if(typeof(unsafeWindow.console) != "undefined" && typeof(unsafeWindow.console.log) != "undefined")
unsafeWindow.console.log(f);
else
GM_log(f);
return arg;
}