function Browser() 
{
  var ua, s, i;

  this.isIE    = false;
  this.isNS    = false;
  this.version = null;

  ua = navigator.userAgent;

  s = "MSIE";
  if ((i = ua.indexOf(s)) >= 0) 
  {
    this.isIE = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  s = "Netscape6/";
  if ((i = ua.indexOf(s)) >= 0) 
  {
    this.isNS = true;
    this.version = parseFloat(ua.substr(i + s.length));
    return;
  }

  // Treat any other "Gecko" browser as NS 6.1.
  s = "Gecko";
  if ((i = ua.indexOf(s)) >= 0) {
    this.isNS = true;
    this.version = 6.1;
    return;
  }
}

var browser = new Browser();

// Global object to hold drag information.
var dragObj = new Object();
dragObj.zIndex = 0;

function dragStartPic(event, id) 
{
  var el;
  var x, y;

  // If an element id was given, find it. Otherwise use the element being clicked on.
  if (id)
    dragObj.elNode = document.getElementById(id);
  else 
  {
    if (browser.isIE)
      dragObj.elNode = window.event.srcElement;
    if (browser.isNS)
      dragObj.elNode = event.target;

    // If this is a text node, use its parent element.
    if (dragObj.elNode.nodeType == 3)
      dragObj.elNode = dragObj.elNode.parentNode;
  }

  // Get cursor position with respect to the page.
  if (browser.isIE) {
    x = window.event.clientX + document.documentElement.scrollLeft
      + document.body.scrollLeft;
    y = window.event.clientY + document.documentElement.scrollTop
      + document.body.scrollTop;
  }
  if (browser.isNS) {
    x = event.clientX + window.scrollX;
    y = event.clientY + window.scrollY;
  }

  // Save starting positions of cursor and element.
  dragObj.cursorStartX = x;
  dragObj.cursorStartY = y;
  dragObj.elStartLeft  = parseInt(dragObj.elNode.style.left, 0);
  dragObj.elStartTop   = parseInt(dragObj.elNode.style.top,  0);

  if (isNaN(dragObj.elStartLeft)) dragObj.elStartLeft = 0;
  if (isNaN(dragObj.elStartTop))  dragObj.elStartTop  = 0;

  // Update element's z-index.
  dragObj.elNode.style.zIndex = ++dragObj.zIndex;

  // Capture mousemove and mouseup events on the page.
  if (browser.isIE) {
    document.attachEvent("onmousemove", dragGoPic);
    document.attachEvent("onmouseup",   dragStopPic);
    document.attachEvent("onmouseout",   dragStopPic);
    window.event.cancelBubble = true;
    window.event.returnValue = false;
  }
  if (browser.isNS) {
    document.addEventListener("mousemove", dragGoPic,   true);
    document.addEventListener("mouseup",   dragStopPic, true);
    document.addEventListener("mouseout",   dragStopPic, true);
    event.preventDefault();
  }
}

function dragGoPic(event) 
{
    // CAREFUL: Specific id for the current project/case.
    var mapContainerForm = document.getElementById("mapContainerForm");
    
  var x, y;
  // Get cursor position with respect to the page.
  if (browser.isIE) {
    x = window.event.clientX + document.documentElement.scrollLeft
      + document.body.scrollLeft;
    y = window.event.clientY + document.documentElement.scrollTop
      + document.body.scrollTop;
  }
  if (browser.isNS) {
    x = event.clientX + window.scrollX;
    y = event.clientY + window.scrollY;
  }

  // Move drag element by the same amount the cursor has moved.
    var startLeft = mapContainerForm.scrollLeft;
    var startTop = mapContainerForm.scrollTop;
    
    var startX = dragObj.cursorStartX;
    var startY = dragObj.cursorStartY;
    
    var scrollLeft = document.documentElement.scrollLeft;
    var scrollTop = document.documentElement.scrollTop;

    
    var movex = 0;
    var movey = 0;
    
    movex = parseInt((startLeft + (startX - x)), 0);
    movey = parseInt((startTop + (startY - y)), 0);
    movex = movex + startLeft;
    movey = movey + startTop;
    
    movex = parseInt(movex / 2);
    movey = parseInt(movey / 2);
    
    mapContainerForm.scrollTop = movey;
    mapContainerForm.scrollLeft = movex;
    
  if (browser.isIE) {
    window.event.cancelBubble = true;
    window.event.returnValue = false;
  }
  if (browser.isNS)
    event.preventDefault();
}

function dragStopPic(event) {

  // Stop capturing mousemove, mouseup and mouseout events.
  if (browser.isIE) {
    document.detachEvent("onmousemove", dragGoPic);
    document.detachEvent("onmouseup",   dragStopPic);
    document.detachEvent("onmouseout",   dragStopPic);
  }
  if (browser.isNS) {
    document.removeEventListener("mousemove", dragGoPic,   true);
    document.removeEventListener("mouseup",   dragStopPic, true);
    document.removeEventListener("mouseout",   dragStopPic, true);
  }
}