Javascript Progress Bar

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//################ Start of progress Bar Class ####################
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//Global parameters
var numOfBullets = 19; // number of bullets in container
var timeInterval = 8;// time interval in seconds to use in auto mode
var progressBarClass; // global parameter to use in Auto mode with setTimeout (DONT DELETE)

//Classes
var ProgressBarClass = Class.create();
ProgressBarClass.prototype = {
    initialize: function(maxStep) 
    {  
    	progressBarClass = this; // set global parameter with the current class instance (dont delete this line. use in Auto method)
		this.timeInterval = timeInterval * 1000;
		this.isAuto = false;
		this.stop = false; // flag to indicate stop of auto increase if bullets
		this.currentStep = 0;		
		this.maxStep = maxStep;
		this.numOfBullets = numOfBullets; //total numer of bullets in progressBar
		this.leftBullets = numOfBullets; // internal count of left bullets to print
		this.OnStepChange = null; //callback to be activate when step is changed
		this.OnFinish = null; //callback to be activate when all steps is finish
    }, 
    //Set the container of the bullets
    SetProgressBarContainer : function(progressBarContainer)
    {
    	this.progressBarContainer = progressBarContainer;
    },
    //set the maxStep number. it also stop if active and reset parameters
    SetMaxStep : function(maxStep)
    {
    	this.Reset();
	   	this.maxStep = maxStep;
    },
    //Add new bullet to the current container
    AddBullet : function( bulletsToPrint, nextInterval )
    {         	
    	var newBullet = document.createElement('IMG');
		newBullet.setAttribute("id", "ImgRec");
		newBullet.src = "images/Progress_Bar_Fill.gif";		
		if(this.progressBarContainer != null)
			this.progressBarContainer.appendChild(newBullet);	
						
		if(bulletsToPrint > 0 )
		{
			setTimeout("progressBarClass.AddBullet(" + (bulletsToPrint - 1) + ", " + nextInterval + ")", nextInterval );
			return;
		}
			
		//increase the current step parameter
		this.currentStep++;
		
		//rize evevnt on step changed
		if(this.OnStepChange != null)
			this.OnStepChange(this.currentStep);	
		
		//Check if this was the last step			
		this.CheckIfEnd();
					
    }, 
    CheckIfEnd : function()
    {
    	if(this.currentStep >= this.maxStep)
		{			
			//rize evevnt on step changed
			if(this.OnFinish != null)
				this.OnFinish();
			return true;
		}
		return false
    },
    //increase the next step
	NextStep : function() 
	{ 		
		//Check if this was the last step
		if(this.CheckIfEnd())
		{
			return;
		}
		
		//calculate the amount of bullets to print and get the loest rount number
    	var bulletsToPrint = Math.floor(this.leftBullets / (this.maxStep - this.currentStep));
    	
    	//if we reached the last step then print the rest
    	if(bulletsToPrint > this.leftBullets)
    		bulletsToPrint = this.leftBullets;
    	
    	//set the left bullets to print
    	this.leftBullets = this.leftBullets - bulletsToPrint;
    	
		//Calculate the time intrval bettwen adding bullts in step	
    	var bulletsInterval = this.timeInterval / bulletsToPrint;
		
		//Start adding bullets for the current step in a loop of the current interval
		this.AddBullet((bulletsToPrint - 1) , bulletsInterval);		
    }, 
    //Start auto increment of bullets in a timer   
    Auto : function() 
	{ 			
		//if its stoped or reached the end then stop and return	
		if((this.stop == true && this.isAuto == true) || this.CheckIfEnd())
		{			
			this.isAuto = false;
			this.stop = false;
			return;
		}
						
		this.isAuto = true;	
		this.stop = false;
				
		this.NextStep();		
		//call this method again
		if(progressBarClass != null)
			setTimeout("progressBarClass.Auto()", this.timeInterval);		
    },
    //stop the auto mode
    Stop : function() 
	{ 	
		this.stop = true;
    },  
    //clear all progressBar parameters and clean bullets
    Reset : function()
    {
	    this.Stop();
    	this.isAuto = false;
		this.currentStep = 0;	
		this.leftBullets = this.numOfBullets;
		if(this.progressBarContainer != null)
			this.progressBarContainer.innerHTML = "";
    }
};

//##############################################################  
//################ End of progress Bar Class ######################
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