变速动动

function getStyle(obj,name){
	return obj.currentStyle?obj.currentstyle[name]:getComputedStyle(obj,false)[name];
};

function move(obj,json,options){
	options=options||{};
	options.time=options.time||700;
	options.type=options.type||‘ease-out‘;

	var start={};
	var dis={};

	for(var name in json){
		if(name==‘opacity‘){
			start[name]=parseFloat(getStyle(obj,name));
		}else{
			start[name]=parseInt(getStyle(obj,name));
		}
		dis[name]=json[name]-start[name];
	};

	var count=Math.round(options.time/30);
	var n=0;

	clearInterval(obj.timer);
	obj.timer=setInterval(function(){
		n++;

		for(var name in json){
			switch(options.type){
				case ‘linear‘:    //匀速
					var cur=start[name]+dis[name]*n/count;
				break;
				case ‘ease-in‘:   //加速
					var a=n/count;
					var cur=start[name]+dis[name]*a*a*a;
				break;
				case ‘ease-out‘:     //减速
					var a=1-n/count;
					var cur=start[name]+dis[name]*(1-a*a*a);
				break;
			}
		};

		if(name==‘opacity‘){
			obj.style.opacity=cur;
			obj.style.filter=‘alpha(opacity:‘+cur*100+‘)‘;
		}else{
			obj.style[name]=cur+‘px‘;
		};

		if(n==count){
			clearInterval(obj.timer);
			options.fn&&options.fn();
		}
	})

}