JS惯性滚动，加速滚动

- 日理万妓 2022-10-29 13:26 123阅读 0赞

<!doctype html>
    <html>
    <head>
    <meta charset="utf-8">
    <title>JS惯性滚动，加速滚动</title>
    <style>
    *{ margin:100; padding:0; list-style:none; font-family: "微软雅黑" }
    #div_bar{width:200px;   background:limegreen; height:40px;position:absolute;left:0;top:0;}
    .box{width:10px;height:10px;background:green; position:absolute;left:0;top:0;}
    
    #div_msg{
    	margin-left:210px;
    	}
    	
    </style>
    
    <script>
    
     
    //滚动事件数组
    let g_arr_wheel = [];
    
    window.onmousewheel = function(){
    
    	var oDiv=document.getElementById('div_bar');
     	
    	let t_dir = event.wheelDeltaY > 0 ? 1 : -1; 
    		
    	let t_wheel_num = g_arr_wheel.length;
    	let t_velocity = 0;
    	
    	//首先删除间隔1000ms以上的 	
    	if(t_wheel_num > 0){
    	
    		let t_old_dir = g_arr_wheel[t_wheel_num-1].wheelDeltaY > 0 ? 1 : -1;
    				
    		if(t_old_dir != t_dir){
    			//方向变了
    			console.log('方向变了-----');
    			g_arr_wheel = [];
    		}else{
    			for(let xe = t_wheel_num-1 ; xe>=0; xe--){
    			
    				let t_cur_wheel = g_arr_wheel[xe]; 
    				
    				let t_time = event.timeStamp - t_cur_wheel.timeStamp;
    								
    				if(t_time > 1000){
    					g_arr_wheel = g_arr_wheel.slice(xe+1);
    					break;
    				}
    			}
    		}
    	}
    		
    	g_arr_wheel.push(event);
    		 
    	t_wheel_num = g_arr_wheel.length;
    	
    	t_velocity = 0;
    		
    	for(let i=0; i<t_wheel_num; i++){
    		let t_delta_y = g_arr_wheel[i].wheelDeltaY;				
    		t_delta_y = Math.abs(t_delta_y) / 120;		 
    		t_velocity += t_delta_y;	
    	}
    	
    	
    	t_velocity = Math.pow(t_velocity, 1.6);
    	t_velocity = t_dir * t_velocity * 3; 
    	t_velocity = t_velocity.toFixed(2);
    	 	
    	let speedX = 0;
    	let speedY = t_velocity;
    	
    	function do_move(obj,speedX,speedY){
            clearInterval(obj.timer);
            obj.timer=setInterval(function(){
                speedX*=0.95;   //摩擦系数
                speedY*=0.95;   //摩擦系数
    		 
                obj.style.left=obj.offsetLeft+speedX+'px';
               
                if(Math.abs(speedX)<1) speedX=0;
                if(Math.abs(speedY)<1) speedY=0;
    			
                if(speedX==0 && speedY==0){
    				console.log('停止定时器---');
                    clearInterval(obj.timer);   
                }
    			
    			let t_top = obj.offsetTop+speedY;
    			if(t_top < 0){
    				t_top = 0;
    				speedY = 0;
    			}
    			 
    			obj.style.top = t_top+'px';
    			
    			var div_msg = document.getElementById('div_msg');
    	
    			let speedYstr = speedY.toFixed(0);
    			t_top = t_top.toFixed(0);
    			div_msg.innerHTML = '速度：'+speedYstr+' <br>距离：'+t_top;
    			 
            },30);  
        }
    	
    	do_move(oDiv,speedX,speedY);
    	
    }
     
    </script>
    </head>
    <body style='overflow:hidden'>
    
    <div id='div_msg'>滚一下试试</div>
     
    <div id="div_bar"> </div>
    </body>
    </html>