function create_XMLHttpRequest() { //create new XHR object
  if (window.XMLHttpRequest)
  {// code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp=new XMLHttpRequest();
  } else {// code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
  }
  return xmlhttp;
}

function fileExists(filename) {
    xmlhttp= create_XMLHttpRequest(); //create new XHR object
    if(!xmlhttp) return false;
    try
    {
        xmlhttp.open("HEAD", filename, false);
        xmlhttp.send(null);
        return (xmlhttp.status==200) ? true : false;
    }
    catch(er)
    {
        return false;
    }
}

function loadXML(XML_filename) {
  xmlhttp= create_XMLHttpRequest();
  xmlhttp.open("GET",XML_filename ,false);
  xmlhttp.send();
  return xmlhttp.responseXML;
}

function xmlToString(xmlDoc){
  if(xmlDoc.xml){
    // MSIE
    xmlString = xmlDoc.xml;
  }else{
    xmlString = (new XMLSerializer).serializeToString(xmlDoc);
  }
  return xmlString;
}

function createString_accordingDate() {
  var today = new Date(); 
  var dd = today.getDate(); 
  var mm = today.getMonth()+1;//January is 0! 
  var yyyy = today.getFullYear(); 
  if(dd<10){dd='0'+dd} ;
  if(mm<10){mm='0'+mm}; 
  return (yyyy + "_" + mm + dd); 
} 

1. Image transition can be controlled programmatically
2. Image can be stretched or centered in the client area of the control
3. Control can show a background image as centered, stretched, or tiled
4. Transition process can use a separate thread
5. New transitional effects can be easily implemented and added.

• x: the numeric variable whose bit to set
• n: which bit to set, starting at 0 for the least-significant (rightmost) bit

• x: the numeric variable whose bit to clear
• n: which bit to clear, starting at 0 for the least-significant (rightmost) bit

• x: the numeric variable to which to write
• n: which bit of the number to write, starting at 0 for the least-significant (rightmost) bit
• b: the value to write to the bit (0 or 1)