var MINSIZE = 50;

function addLink(elem) {
	elem.innerHTML += "<p>Veja mais em <a href='" + window.location.href + "'>" + document.title + "</a></p>";
}

function onCopy () {
    var elem = document.createElement("div");
	
    elem.style.position = "fixed";
    elem.style.left = "-9999px";
    
    document.getElementsByTagName("body")[0].appendChild(elem);
    
    if (document.all) {
        sel = document.selection.createRange();
	    elem.innerHTML = sel.htmlText;
        if (elem.innerHTML.length < MINSIZE)
            return;
	    addLink(elem);
        range = document.body.createTextRange();
        range.moveToElementText(elem);
        range.select();
    } else {
        sel = window.getSelection();
        if (sel.getRangeAt) {
            var range = sel.getRangeAt(0);
        } else {
            var range = document.createRange ();
            range.setStart (sel.anchorNode, sel.anchorOffset);
            range.setEnd (sel.focusNode, sel.focusOffset);
        }
        elem.appendChild(range.cloneContents());
        if (elem.innerHTML.length < MINSIZE)
            return;
        addLink(elem);
        range = document.createRange();
        sel.removeAllRanges();  
        range.selectNodeContents(elem);
        sel.addRange(range);
    }
    
    
}

function checkCopy(ev){
    ev = ev || window.event;
    var kCode = ev.keyCode || ev.which; 
    if (ev.ctrlKey && kCode == 67) { // ctrl+c
        onCopy();
    }
}

function addEvent(el, ev, func){
    if (el.addEventListener) {
        el.addEventListener(ev, func, false);
    } else if (el.attachEvent) {
        el.attachEvent("on" + ev, func);
    }
}

//Function taken from http://perfectionkills.com/detecting-event-support-without-browser-sniffing/
function isMouseEventSupported(eventName) {
    var el = document.createElement('div');
    eventName = 'on' + eventName;
    var isSupported = (eventName in el);
    if (!isSupported) {
        el.setAttribute(eventName, 'return;');
        isSupported = typeof el[eventName] == 'function';
    }
    el = null;
    return isSupported;
}

addEvent(window, "load", function(){
    if (isMouseEventSupported("copy")){
        addEvent(document.body, "copy", onCopy);
    }else{
        addEvent(document, "keydown", checkCopy);
    }
});