/* This script and many more are available free online at
The JavaScript Source :: http://javascript.internet.com
Created by: Steve Chipman :: http://slayeroffice.com/
 */

 // constants to define the title of the alert and button text.
var ALERT_TITLE = "Oops!";
var ALERT_BUTTON_TEXT = "Close";

// over-ride the alert method only if this a newer browser.
// Older browser will see standard alerts
if(document.getElementById) {
 window.alert = function(txt) {
   createCustomAlert(txt);
 }
}

function createCustomAlert(txt) {
 // shortcut reference to the document object
 d = document;

 // if the modalContainer object already exists in the DOM, bail out.
 if(d.getElementById("modalContainer")) return;

 // create the modalContainer div as a child of the BODY element
 mObj = d.getElementsByTagName("body")[0].appendChild(d.createElement("div"));
 mObj.id = "modalContainer";
  // make sure its as tall as it needs to be to overlay all the content on the page
 mObj.style.height = document.documentElement.scrollHeight + "px";

 // create the DIV that will be the alert
 alertObj = mObj.appendChild(d.createElement("div"));
 alertObj.id = "alertBox";
 // MSIE doesnt treat position:fixed correctly, so this compensates for positioning the alert
 if(d.all && !window.opera) alertObj.style.top = document.documentElement.scrollTop + "px";
 // center the alert box
 alertObj.style.left = (d.documentElement.scrollWidth - alertObj.offsetWidth)/2 + "px";

 // create an H1 element as the title bar
 h1 = alertObj.appendChild(d.createElement("h1"));
 h1.appendChild(d.createTextNode(ALERT_TITLE));

 // create a paragraph element to contain the txt argument
 msg = alertObj.appendChild(d.createElement("p"));
 msg.innerHTML = txt;

 // create an anchor element to use as the confirmation button.
 btn = alertObj.appendChild(d.createElement("a"));
 btn.id = "closeBtn";
 btn.appendChild(d.createTextNode(ALERT_BUTTON_TEXT));
 btn.href = "#";
 // set up the onclick event to remove the alert when the anchor is clicked
 btn.onclick = function() { removeCustomAlert();return false; }
}

// removes the custom alert from the DOM
function removeCustomAlert() {
 document.getElementsByTagName("body")[0].removeChild(document.getElementById("modalContainer"));
}