var go = function () {
    document.getElementById('output').value = parse(document.getElementById('input').value);
};

var parse = function (t) {
    var output = '', dn, asin;
    var ls = t.split(/\n/);
    for (i in ls) {
        if (/http:\/\/www\.amazon\.[\w\.]{2,6}\/.+[A-Z0-9]{10}.*/.test(ls[i])) {
            var fs = ls[i].split(/[\/\?\s]/);
            for (j in fs) {
                if (/^www\.amazon\.[\w\.]{2,6}$/.test(fs[j])) {
                    dn = fs[j];
                } else if (/^[A-Z0-9]{10}$/.test(fs[j])) {
                    asin = fs[j]
                }
            }
            output += 'http://' + dn + '/dp/' + asin;
        }
        else {
            output += ls[i];
        }
        if (ls.length-1 >= i) {
            output += '\n';
        }
    }
    return output;
};

document.getElementById('output').onfocus = function () {this.select();};
document.getElementById('input').onkeydown = 
document.getElementById('input').onblur = 
document.getElementById('input').onchange = go;

go();