// JavaScript Document
function change_pictures(picture_url,tt,lk)
{
	var bg = document.getElementById("show_left_img_display");
	var bgt = document.getElementById("titles_bg");
	var bgl= document.getElementById("show_link");
	bgl.href=lk;
	bgt.innerHTML=tt;
	bg.style.backgroundImage = picture_url;	

	function start_change_1()
	{
			picture_widht = 190;
			picture_height = 162;
			widht = 0;
			height = 0;
			moveing_widht = picture_widht+widht;
			changeing_1();
			function changeing_1()
			{
				if (moveing_widht >widht)
				{
					moveing_widht = moveing_widht - 1;
					bg.style.backgroundPosition = moveing_widht+"px "+height+"px";
					setTimeout(changeing_1,1);
				}
			}
	}
	
	
	
	function start_change_2()
	{
			picture_widht = 190;
			picture_height = 162;
			widht = 0;
			height = 0;
			moveing_widht = -picture_widht;
			changeing_2();
			function changeing_2()
			{
				if (moveing_widht < widht)
				{
					moveing_widht = moveing_widht + 1;
					bg.style.backgroundPosition = moveing_widht+"px "+height+"px";
					setTimeout(changeing_2,1);
				}
			}
	}
	
	
		function start_change_3()
		{
				picture_widht = 190;
				picture_height = 162;
				widht = 0;
				height = 0;
				mvh = picture_height;
				changeing_3();
				function changeing_3()
				{
					if (mvh >height)
					{
							
						mvh = mvh - 1;
						bg.style.backgroundPosition = 0+"px "+mvh+"px";
						setTimeout(changeing_3,1);
					}
				}
		}
	
	
	
		function start_change_4()
		{
				picture_widht = 190;
				picture_height = 162;
				widht = 0;
				height = 0;
				mvh = -picture_height;
				changeing_4();
				function changeing_4()
				{
					if (mvh<height)
					{
						mvh = mvh + 1;
						bg.style.backgroundPosition = 0+"px "+mvh+"px";
						setTimeout(changeing_4,1);
					}
				}
		}
	


		
			//声明一个随机数变量，默认为1
	var GetRandomn = 1;
	//获取随机范围内数值的函数
	function GetRandom(n){GetRandomn=Math.floor(Math.random()*n+1)}
	//开始调用，获得一个1-100的随机数
	GetRandom("4");
	//输出查看
	switch(GetRandomn) 
	{
		case 1: 
		start_change_1();
		break;
		
		case 2: 
		start_change_2();
		break;
		
		case 3: 
		start_change_3();
		break;
		
		case 4: 
		start_change_4();
		break;
	}


}