function Zoom(){
		this._isInit = false;
		this._zoom = 1;
		this._zoom_w = 1;
		this._zoom_h = 1;
		this._w = 1440;
		this._h = 900;
		this._cw = window.screen.width;
		this._ch = window.screen.height;
		this._getZoom = function(){
			if(!this._isInit){
				this._init();
			}
			return this._zoom;
		};
		this._getZoom_w = function(){
			if(!this._isInit){
				this._init();
			}
			return this._zoom_w;
		};
		this._getZoom_h = function(){
			if(!this._isInit){
				this._init();
			}
			return this._zoom_h;
		};
		this._init = function(){
		/*	this._zoom = (this._cw/this._w>this._ch/this._h)?this._ch/this._h:this._cw/this._w;
			this._zoom_w = this._cw/this._w;
			this._zoom_h = this._ch/this._h;*/
		};
}
var _global_zoom = new Zoom();

function getZoom(){//图片所放值
	if(_global_zoom == null){
		_global_zoom = new Zoom();
	}
	_global_zoom._getZoom();
}
function getZoom_H(){//单纯高度缩放值
	if(_global_zoom == null){
		_global_zoom = new Zoom();
	}
	_global_zoom._getZoom_h();
}
function getZoom_W(){//宽度所放值
	if(_global_zoom == null){
		_global_zoom = new Zoom();
	}
	_global_zoom._getZoom_w();
}