复制代码代码如下: <html> <head> <meta charset=utf-8> <title>跳跳球</title> [removed] //box var box_x=0; var box_y=0; var box_width=300; var box_height=300; //注意:定位球采用球的中心 var ball_x=10; var ball_y=10; var ball_radius=10; var ball_vx=5; var ball_vy=3; var box_bound_left=box_x+ball_radius; var box_bound_right=box