cnblogs/dcrenl/数字雨（Javascript使用canvas绘制Matrix，效果很赞哦）.html

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<span style="color: #0000ff;">&lt;</span><span style="color: #800000;">canvas </span><span style="color: #ff0000;">id</span><span style="color: #0000ff;">="q"</span><span style="color: #0000ff;">&gt;&lt;/</span><span style="color: #800000;">canvas</span><span style="color: #0000ff;">&gt;</span>
<span style="color: #0000ff;">&lt;</span><span style="color: #800000;">script</span><span style="color: #0000ff;">&gt;</span>
<span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> s </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> window.screen;
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> width </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> q.width </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> s.width;
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> height </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> q.height </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> s.height;
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> letters </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> Array(</span><span style="background-color: #f5f5f5; color: #000000;">256</span><span style="background-color: #f5f5f5; color: #000000;">).join(</span><span style="background-color: #f5f5f5; color: #000000;">1</span><span style="background-color: #f5f5f5; color: #000000;">).split(</span><span style="background-color: #f5f5f5; color: #000000;">''</span><span style="background-color: #f5f5f5; color: #000000;">);
</span><span style="background-color: #f5f5f5; color: #0000ff;">var</span><span style="background-color: #f5f5f5; color: #000000;"> draw </span><span style="background-color: #f5f5f5; color: #000000;">=</span> <span style="background-color: #f5f5f5; color: #0000ff;">function</span><span style="background-color: #f5f5f5; color: #000000;"> () {
  q.getContext(</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">2d</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">).fillStyle</span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">rgba(0,0,0,.05)</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">;
  q.getContext(</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">2d</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">).fillRect(</span><span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;">,</span><span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;">,width,height);
  q.getContext(</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">2d</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">).fillStyle</span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">#0F0</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">;
  letters.map(</span><span style="background-color: #f5f5f5; color: #0000ff;">function</span><span style="background-color: #f5f5f5; color: #000000;">(y_pos, index){
    text </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> String.fromCharCode(</span><span style="background-color: #f5f5f5; color: #000000;">34</span><span style="background-color: #f5f5f5; color: #000000;">+</span><span style="background-color: #f5f5f5; color: #000000;">Math.random()</span><span style="background-color: #f5f5f5; color: #000000;">*</span><span style="background-color: #f5f5f5; color: #000000;">33</span><span style="background-color: #f5f5f5; color: #000000;">);
</span><span style="background-color: #f5f5f5; color: #008000;">//</span><span style="background-color: #f5f5f5; color: #008000;">    text = String.fromCharCode(3e4+Math.random()*33);//显示中文</span>
<span style="background-color: #f5f5f5; color: #000000;">    x_pos </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> index </span><span style="background-color: #f5f5f5; color: #000000;">*</span> <span style="background-color: #f5f5f5; color: #000000;">10</span><span style="background-color: #f5f5f5; color: #000000;">;
    q.getContext(</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">2d</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">).fillText(text, x_pos, y_pos);
    letters[index] </span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;"> (y_pos </span><span style="background-color: #f5f5f5; color: #000000;">&gt;</span> <span style="background-color: #f5f5f5; color: #000000;">758</span> <span style="background-color: #f5f5f5; color: #000000;">+</span><span style="background-color: #f5f5f5; color: #000000;"> Math.random() </span><span style="background-color: #f5f5f5; color: #000000;">*</span> <span style="background-color: #f5f5f5; color: #000000;">1e4</span><span style="background-color: #f5f5f5; color: #000000;">) </span><span style="background-color: #f5f5f5; color: #000000;">?</span> <span style="background-color: #f5f5f5; color: #000000;">0</span><span style="background-color: #f5f5f5; color: #000000;"> : y_pos </span><span style="background-color: #f5f5f5; color: #000000;">+</span> <span style="background-color: #f5f5f5; color: #000000;">10</span><span style="background-color: #f5f5f5; color: #000000;">;
    q.getContext(</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">2d</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">).fillStyle</span><span style="background-color: #f5f5f5; color: #000000;">=</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">#</span><span style="background-color: #f5f5f5; color: #000000;">'</span><span style="background-color: #f5f5f5; color: #000000;">+</span><span style="background-color: #f5f5f5; color: #000000;">letters[index];
  });
};
setInterval(draw, </span><span style="background-color: #f5f5f5; color: #000000;">33</span><span style="background-color: #f5f5f5; color: #000000;">);
</span><span style="color: #0000ff;">&lt;/</span><span style="color: #800000;">script</span><span style="color: #0000ff;">&gt;</span>
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