var bgimg=['http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body1.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body2.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body3.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body4.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body5.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body6.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body7.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body8.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body9.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body10.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body11.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body12.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body13.jpg',
 				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body14.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body15.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body16.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body16_1.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body16_2.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body16_3.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body17.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body17_1.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body17_2.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body17_3.jpg',
 				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body18.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body18_1.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body18_2.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body18_3.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body19.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body19_1.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body19_2.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body19_3.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body20.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body20_1.jpg',
				'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body20_2.jpg',
			   'http://vimg.ifeng.com/2008/06/14/1736562509/finalbg/body20_3.jpg'];
			   
	function setBackgound(){		   
		var i=Math.floor(Math.random()*35);	
		document.body.style.background="url('" + bgimg[i] + "') no-repeat #151515 top center;";   
	}