// JavaScript Document
	// DOM
	function getObjectRef(name) {
		if(document.getElementById)
			return document.getElementById(name);
		else if(document.all) 
			return document.all[name];
		else 
			return null;
	}
	// CSS
	function bgChang(color){
		this.css.backgroundColor=color; 
		this.css.bgColor=color; 
		this.css.background=color;
	}
	// general functions to assist the script
	//========================================
	function show(name) {
		var el = getObjectRef(name);
		if(el) 
			el.style.visibility = "visible";
	}
	function hide(name) {
		var el = getObjectRef(name);
		if(el) 
			el.style.visibility = "hidden";
	}
	function getWidth(name) {
		var el = getObjectRef(name);
		return el.offsetWidth;
	}
	function getHeight(name) {
		var el = getObjectRef(name);
		return el.offsetHeight;
	}
	function moveMeTo(name,x,y) {
		var el = getObjectRef(name);
		if(el) { 
			el.style.top = parseInt(y); 
			el.style.left = parseInt(x); 
		}  
	}
	function moveMeBy(name,x,y) {
		var el = getObjectRef(name);
		if(el) { 
			el.style.top = parseInt(el.style.top) + parseInt(y); 
			el.style.left = parseInt(el.style.left) + parseInt(x); 
		}  
	}
	// Math functions
	//================
	var pi = Math.PI;
	function square(x) { 
		return (x*x);
	}
	function sqrt(x) { 
		return Math.sqrt(x); 
	}
	function round(x) { 
		return Math.round(x); 
	}
	function rand(x,y) { 
		return (round(Math.random()*(y-x)) + x); 
	}
	function cos(x) { 
		return Math.cos(x)
	 }
	function sin(x) { 
		return Math.sin(x) 
	}
	function degToRad(x) { 
		return ( x/(360/(2*pi)) ); 
	}
	function radToDeg(x) { 
		return ( x*(360/(2*pi)) );
	}
	function atan(s,t) {
		if( s == 0.0 && t > 0.0)
			angle = 90.0;
		else if(s == 0.0 && t < 0.0) 
			angle = 270.0;
		else if (s < 0.0 ) 
			angle = 180.0 + radToDeg(Math.atan(t/s));
		else if (s > 0.0 && t < 0.0)
			angle = 360.0 + radToDeg(Math.atan(t/s));
		else {
			if(s==0.0) s=0.00001;
				angle = radToDeg(Math.atan(t/s));
		}
		if(angle < 0.0) angle += 360.0;
			return angle;
	}