/*
  by Paul@YellowPencil.com and Scott@YellowPencil.com
  includes TextResizeDetector by Lawrence Carvalho <carvalho@uk.yahoo-inc.com>
  feel free to delete all comments except for the above credit
*/

// Replace 'center' 'right' and 'left' with the ID names of the columns you want to balance.
// The last one is there to show how you can add more columns.  Just delete the ones you're not using.
var divs = new Array('col1', 'col2', 'col3');
var divBottoms = new Array('col1_bottom','col2_bottom','col3_bottom');

// Initialize Scripts - is this a browser that understands DOM?
function scriptInit() { if (!document.getElementById) { return; } }

// Set up Event Listener
function addEvent(elm, evType, fn, useCapture) { 
  if (elm.addEventListener) { elm.addEventListener(evType, fn, useCapture); return true; } 
  else if (elm.attachEvent) { var r = elm.attachEvent('on' + evType, fn); return r; }
  else { elm['on' + evType] = fn; }
}

// Start Column Script
function setTall() {
  if (document.getElementById) { var maxHeight = 0; for (var i = 0; i < divs.length; i++) {
      if (document.getElementById(divs[i]) != null)
      { var div = document.getElementById(divs[i]); div.style.height = null; if (div.offsetHeight > maxHeight) maxHeight = div.offsetHeight; }
    }
  maxHeight = maxHeight + 25;                               
  for (var i = 0; i < divs.length; i++) {
      if (document.getElementById(divs[i]) != null)
      { var div = document.getElementById(divs[i]); div.style.height = maxHeight + 'px'; if (div.offsetHeight > maxHeight) { div.style.height = (maxHeight - (div.offsetHeight - maxHeight)) + 'px'; } }
    }
  }
  for (var i = 0; i < divBottoms.length; i++) {
      if (document.getElementById(divBottoms[i]) != null)
      { var div = document.getElementById(divBottoms[i]); div.style.top = (maxHeight - div.offsetHeight - 3)  + 'px'}
  }
}

// Assign one of the columns to the TextResizeDetector.
function initTall() {
  if (document.getElementById) { for (var i = 0; i < divs.length; i++)
    { if (document.getElementById(divs[i]) != null) { TextResizeDetector.TARGET_ELEMENT_ID = divs[i]; break; } }
  setTall(); } 
}

// Fire Events
addEvent(window, 'load', initTall, false);
addEvent(window, 'resize', setTall, false);

/*  Detects changes to font sizes when user changes browser settings
  Fires a custom event with the following data:
  iBase  : base font size
  iDelta : difference in pixels from previous setting
  iSize  : size in pixel of text
  author Lawrence Carvalho carvalho@uk.yahoo-inc.com */

// @constructor
TextResizeDetector = function() {
    var el  = null;
  var iIntervalDelay  = 200;
  var iInterval = null;
  var iCurrSize = -1;
  var iBase = -1;
   var aListeners = [];
   var createControlElement = function() {
     el = document.createElement('span');
    el.id='textResizeControl';
    el.innerHTML='&nbsp;';
    el.style.position="absolute";
    el.style.left="-9999px";
    var elC = document.getElementById(TextResizeDetector.TARGET_ELEMENT_ID);
    // insert before firstChild
    if (elC)
      elC.insertBefore(el,elC.firstChild);
    iBase = iCurrSize = TextResizeDetector.getSize();
   };

   function _stopDetector() {
    window.clearInterval(iInterval);
    iInterval=null;
  };
  function _startDetector() {
    if (!iInterval) {
      iInterval = window.setInterval('TextResizeDetector.detect()',iIntervalDelay);
    }
  };

    function _detect() {
     var iNewSize = TextResizeDetector.getSize();

     if(iNewSize!== iCurrSize) {
      for (var   i=0;i <aListeners.length;i++) {
        aListnr = aListeners[i];
        var oArgs = {  iBase: iBase,iDelta:((iCurrSize!=-1) ? iNewSize - iCurrSize + 'px' : "0px"),iSize:iCurrSize = iNewSize};
        if (!aListnr.obj) {
          aListnr.fn('textSizeChanged',[oArgs]);
        }
        else  {
          aListnr.fn.apply(aListnr.obj,['textSizeChanged',[oArgs]]);
        }
      }

     }
     return iCurrSize;
   };
  var onAvailable = function() {
    if (!TextResizeDetector.onAvailableCount_i ) {
      TextResizeDetector.onAvailableCount_i =0;
    }

    if (document.getElementById(TextResizeDetector.TARGET_ELEMENT_ID)) {
      TextResizeDetector.init();
      if (TextResizeDetector.USER_INIT_FUNC){
        TextResizeDetector.USER_INIT_FUNC();
      }
      TextResizeDetector.onAvailableCount_i = null;
    }
    else {
      if (TextResizeDetector.onAvailableCount_i<600) {
             TextResizeDetector.onAvailableCount_i++;
        setTimeout(onAvailable,200)
      }
    }
  };
  setTimeout(onAvailable,500);

   return {
       /*
        * Initializes the detector
        *
        * @param {String} sId The id of the element in which to create the control element
        */
       init: function() {

         createControlElement();
        _startDetector();
       },
      /**
       * Adds listeners to the ontextsizechange event.
       * Returns the base font size
       *
       */
       addEventListener:function(fn,obj,bScope) {
        aListeners[aListeners.length] = {
          fn: fn,
          obj: obj
        }
        return iBase;
      },
      /**
       * performs the detection and fires textSizeChanged event
       * @return the current font size
       * @type {integer}
       */
       detect:function() {
         return _detect();
       },
       /**
        * Returns the height of the control element
        *
       * @return the current height of control element
       * @type {integer}
        */
       getSize:function() {
           var iSize;
           return el.offsetHeight;


       },
       /**
        * Stops the detector
        */
       stopDetector:function() {
        return _stopDetector();
      },
      /*
       * Starts the detector
       */
       startDetector:function() {
        return _startDetector();
      }
   }
 }();

/*** end TextResizeDetector */

TextResizeDetector.TARGET_ELEMENT_ID = 'doc';
TextResizeDetector.USER_INIT_FUNC = function() {
  var iBase = TextResizeDetector.addEventListener(setTall, null);
};