html読み込みの進捗状況を表示するjavascriptのプログレスバー

以下のコードのcoutUp functionをhtmlの途中に埋め込むことで、そのhtmlページの読み込みの進捗状況を表示することができます。（こういう方法がいいかどうかはわかりませんが。）

function ProgressBar(id)
{

  this.div = setProgressDIV(id);
  this.init = init;
  this.countUp = countUp;
  var progress;

  function setProgressDIV(id)
  {
    if(!id){
      id = "_progress"+(new Date()).getTime();
      var creprgDIV = document.createElement("DIV") ;
      this.div = document.body.appendChild(creprgDIV) ;
      this.div.setAttribute("id",id) ;

      this.div.style.position = "relative";
      this.div.style.top      = "0px";
      this.div.style.left     = "0px";
      this.div.style.width    = "0px";
      this.div.style.height   = "0px";

    } else {
      this.div = document.getElementById(id)
    }

    this.div.style.color = 'blue'  ;
    this.div.style.margin = '0px' ;
    this.div.style.padding = '4px';

    this.div.prog_bar= '|';
    this.div.prog_count =0;
    this.div.prog_count_max =50;

    this.div.prog_array= [];
    return this.div
  }

  function init(arg){
    this.div.innerHTML = '' ;
    this.div.count =0;
    this.div.barcount = 0.001;
    this.div.prog_count_max = arg;
    this.div.style.height ="12px";
    this.div.style.width ="auto";
  } 

  function countUp(){
    if(this.div.count >= this.div.prog_count_max){
       this.div.innerHTML = 'Load completed.';
    }
    else{
      this.div.count++;
      this.div.barcount += 10.0/this.div.prog_count_max;
      while(this.div.barcount >= 1.0){
        this.div.barcount = this.div.barcount - 1.0;
        this.div.innerHTML += this.div.prog_bar;
      }
    }
  }
  return this;
}
function setUp(arg) {
 progress = new ProgressBar('nowloading');
 progress.init(arg);
}

function countUp(){
 progress.countUp();
}