// Classe Modal

function Modal(alpha){
 	
	if(!document.getElementById('modal')){
		
		_this 							= this;
		_this.cont 						= document.createElement('DIV');
		_this.cont.id 					= 'modal';
		this.cont.style.float 			= "none";
		this.cont.style.position 		= "absolute";
		this.cont.style.left 			= '0px';
		this.cont.style.top 			= '0px';
		this.cont.style.width 			= screen_width+'px';
		this.cont.style.height 			= scroll_height+'px';
		this.cont.style.backgroundColor = '#000000';
		this.cont.style.filter 			= 'alpha(opacity='+alpha+')';
		this.cont.style.MozOpacity		= "."+(alpha/10)+"0";
		//this.cont.style.zIndex 			= 80;

		document.body.style.overflow = 'hidden';
		document.body.appendChild(this.cont);

	}
	
	
	_this.destroy = function(){
		removeDom(_this.cont);
		document.body.style.overflow = 'visible';
	}
		
	
}