html5彈跳球示例代碼

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    彈跳球使用html5實(shí)現(xiàn),不必驚訝,使用html5完全可以實(shí)現(xiàn),具體的截圖及代碼如下,感興趣的朋友可以參考下哈,希望對(duì)大家有所幫助
    代碼如下:
    <html>
    <head>
    <meta charset=utf-8>
    <title>跳跳球</title>
    <script>
    //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_x+box_width-ball_radius;
    var box_bound_top=box_y+ball_radius;
    var box_bound_bottom=box_y+box_height-ball_radius;
    //ball
    //context
    var ctx;
    function init()
    {
    ctx=document.getElementById('canvas').getContext('2d');
    ctx.lineWidth=ball_radius;
    ctx.fillStyle="rgb(200,0,50)";
    move_ball();
    setInterval(move_ball,100);//note
    }
    function move_ball()
    {
    ctx.clearRect(box_x,box_y,box_width,box_height);
    move_and_check();
    ctx.beginPath();
    ctx.arc(ball_x,ball_y,ball_radius,0,Math.PI*2,true);
    ctx.fill();
    ctx.strokeRect(box_x,box_y,box_width,box_height);
    }
    function move_and_check()
    {
    var cur_ball_x=ball_x+ball_vx;
    var cur_ball_y=ball_y+ball_vy;
    if(cur_ball_x<box_bound_left)
    {
    ball_vx=-ball_vx;
    cur_ball_x=box_bound_left;
    }
    if(cur_ball_x>box_bound_right)
    {
    ball_vx=-ball_vx;
    cur_ball_x=box_bound_right;
    }
    if(cur_ball_y<box_bound_top)
    {
    ball_vy=-ball_vy;
    cur_ball_y=box_bound_top;
    }
    if(cur_ball_y>box_bound_bottom)
    {
    ball_vy=-ball_vy;
    cur_ball_y=box_bound_bottom;
    }
    ball_x=cur_ball_x;
    ball_y=cur_ball_y;
    }
    </script>
    </head>
    <body onLoad="init()">
    <canvas id="canvas" width="400" height="400"/>
    </body>
    </html>