// Show the QR-Code of a permalink (when the QR-Code icon is clicked).
function showQrCode(caller,loading)
{ 
    // Dynamic javascript lib loading: We only load qr.js if the QR code icon is clicked:
    if (typeof(qr) == 'undefined') // Load qr.js only if not present.
    {
        if (!loading)  // If javascript lib is still loading, do not append script to body.
        {
            var element = document.createElement("script");
            element.src = "plugins/qrcode/qr-1.1.3.min.js";
            document.body.appendChild(element);
        }
        setTimeout(function() { showQrCode(caller,true);}, 200); // Retry in 200 milliseconds.
        return false;
    }

    // Remove previous qrcode if present.
    removeQrcode();
    
    // Build the div which contains the QR-Code:
    var element = document.createElement('div');
    element.id = 'permalinkQrcode';

	// Make QR-Code div commit sepuku when clicked:
    if ( element.attachEvent ){
        element.attachEvent('onclick', 'this.parentNode.removeChild(this);' );

    } else {
        // Damn IE
        element.setAttribute('onclick', 'this.parentNode.removeChild(this);' );
    }
    
    // Build the QR-Code:
    var image = qr.image({size: 8,value: caller.dataset.permalink});
    if (image)
    { 
        element.appendChild(image);
        element.innerHTML += "<br>Click to close";
        caller.parentNode.appendChild(element);

        // Show the QRCode
        qrcodeImage = document.getElementById('permalinkQrcode');
        // Workaround to deal with newly created element lag for transition.
        window.getComputedStyle(qrcodeImage).opacity;
        qrcodeImage.className = 'show';
    }
    else
    {
        element.innerHTML = "Your browser does not seem to be HTML5 compatible.";
    }
    return false;
}

// Remove any displayed QR-Code
function removeQrcode()
{
    var elem = document.getElementById('permalinkQrcode');
    if (elem) {
        elem.parentNode.removeChild(elem);
    }
    return false;
}