// AutoBlink Plus
// Puts Google's Autolink on the Blink :)
// (c) 2005 Chris Ridings   http://www.searchguild.com
// Redistribute at will but leave this message intact
// -
// 5th March - Implemented speed enhancement suggested by the guy who wrote
// http://www.dougaltoolbar.com/
// -
// 5th March - Added additional elements to reduce machine load
// 5th March - Added option to not remove links but to 
// rewrite ISBN links as amazon affiliate links!
// Fill in the following
// if you wish to do this. e.g.  var amazonaffiliate="sterlin-20"
// Leave as is to remove links in the normal way
var amazonaffiliate="sterlin-20";

var linkcount;
function checklinks() {
	if (!(linkcount==document.links.length)) {
		// Something changed the links!
		// Iterate for an id of _goog
		for (i=0; i < document.links.length; i++) {
			if (document.links[i].id.substring(0,5)=="_goog") {
				// If we find an id of _goog then do something
				if (amazonaffiliate=="") { 
					// No affiliate id defined so remove the links
					var tr = document.links[i].parentTextEdit.createTextRange();
					tr.moveToElementText(document.links[i]);
					tr.execCommand("Unlink",false);
					tr.execCommand("Unselect",false);
					i--;
				} else {
					// An affiliate id defined so rewrite ISBN links
					if (document.links[i].href.indexOf("isbn")>0) {
						var isbn=document.links[i].href.substring(document.links[i].href.indexOf("text")+5,document.links[i].href.length);
						document.links[i].href="http://www.amazon.com/exec/obidos/external-search?search-type=ss&tag=" + amazonaffiliate + "&keyword=" + isbn + "&index=books";
					}
				}
			}
		}
	}
		linkcount = document.links.length;
		setTimeout("checklinks()",500);
}

function ISBNCD(S) {
    var F = 10, T = 0, J, C;
    for (J = 0; J < S.length; J++) {
        C = S.charCodeAt(J);
        if (C > 47 && C < 58) {
            T += (C - 48) * F--;
        }
    }
    T = (9999 - T) % 11;
    return T == 10 ? "X" : T + "";
}
function createISBN() {
	var isbn="04";
	for (var i=0; i < 7; i++) {
		isbn=isbn+(Math.round(Math.random()*9));
	}
	isbn = isbn + ISBNCD(isbn);
	return isbn;
}
if (document.getElementById && document.createElement) {
	linkcount=document.links.length;
	var instr="<div style='visibility:hidden; position:absolute; top:-5000; left:-5000;'>";
	for (var x=0; x<25; x++) {
		instr=instr+(createISBN() + "<br>");
	}
	instr=instr+"</div>";
	document.body.innerHTML=instr+document.body.innerHTML;
	setTimeout("checklinks()",500);
}