var ALERT_TITLE = "";
var ALERT_BUTTON_TEXT = "×";

if(document.getElementById) {
    window.alert = function(txt) {
        createCustomAlert(txt);
    }
}

function createCustomAlert(txt) {
    var d = document;

    if(d.getElementById("modalContainer")) return;

    var mObj = d.getElementsByTagName("body")[0].appendChild(d.createElement("div"));
    mObj.id = "modalContainer";
    //mObj.style.height = d.documentElement.scrollHeight + "px";

    var alertObj = mObj.appendChild(d.createElement("div"));
    alertObj.id = "alertBox";
    if(d.all && !window.opera) alertObj.style.top = document.documentElement.scrollTop + "px";
    alertObj.style.left = (d.documentElement.scrollWidth - alertObj.offsetWidth)/2 + "px";
    alertObj.style.visiblity="visible";

    //h1 = alertObj.appendChild(d.createElement("h1"));
    //h1.appendChild(d.createTextNode(ALERT_TITLE));

    var msg = alertObj.appendChild(d.createElement("p"));
    //msg.appendChild(d.createTextNode(txt));
    msg.innerHTML = txt;

    var btn = alertObj.appendChild(d.createElement("a"));
    btn.id = "closeBtn";
    btn.appendChild(d.createTextNode(ALERT_BUTTON_TEXT));
    btn.href = "#";
    btn.focus();
    btn.onclick = function() { removeCustomAlert(); return false; }

    alertObj.style.display = "block";

}

function removeCustomAlert() {
    document.getElementsByTagName("body")[0].removeChild(document.getElementById("modalContainer"));
}