实现打字效果

<div id="main">
        <div id="content">
            <div id="code">
                <span class="col_3f7f5f">/**</span><br />
                <span class="space"/><span class="col_3f7f5f">* I became a small company programmer,</span><br />
                <span class="space"/><span class="col_3f7f5f">* So I want to wish you a happy birthday in a different way.</span><br />
                <span class="space"/><span class="col_3f7f5f">*/</span><br />
                Boy i = <span class="col_7f0055">new</span> Boy(<span class="col_2a36ff">"HeheWang"</span>);<br />
                Girl u = <span class="col_7f0055">new</span> Girl(<span class="col_2a36ff">"BigBoss"</span>);<br />
                <span class="col_3f7f5f">// February 20, 2015, I tell you to be my girlfriend. </span><br />
                i.love(u);<br />
                <span class="col_3f7f5f">// Forget your facial expression, may be surprised.</span><br />
                <span class="col_3f7f5f">// Luckily, You took my girlfriend.</span><br />
                u.agree(i);<br />
                <span class="col_3f7f5f">// After, I miss u every day.</span><br />
                i.miss(u);<br />
                <span class="col_3f7f5f">// And care for u and our love.</span><br />
                i.carefor(u);<br />
                <span class="col_3f7f5f">// Until we start to quarrel.</span><br />
                i.quarrel(u);<br />
                <span class="col_3f7f5f">// Soon we‘ll be fine.</span><br />
                fine(i,u);<br />
                <span class="col_3f7f5f">// March 18th is your birthday.</span><br />
                <span class="col_7f0055">number</span> days = <span class="col_7f0055">0</span>;<br />
                <span class="col_7f0055">while</span> (days < 365) {<br />
                <span class="ml_15"/>u happy;<br />
                <span class="ml_15"/>days++<br />
                <span class="ml_15"/><span class="col_3f7f5f">// I hope u can live a more meaningful life</span><br />
                <span class="ml_15"/><span class="col_3f7f5f">// And healthy.</span><br />
                }<br />
                <span class="col_3f7f5f">// You say that you won‘t be so easy to marry me.</span><br />
                <span class="col_3f7f5f">// So I will try my best to let you marry me.</span><br />
                i tryhard();<br />
                <span class="col_3f7f5f">// Until one day I can marry you.</span><br />
                i.marry(u);<br />
                i.liveHappilyWith(u);<br />
            </div>
        </div>
    </div>

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