<pre style="word-wrap: break-word; white-space: pre-wrap;">&lt;!DOCTYPE html&gt;
&lt;html lang="en"&gt;
&lt;head&gt;
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    &lt;title&gt;Document&lt;/title&gt;

    

&lt;/head&gt;
&lt;body&gt;
    
    &lt;h1&gt;test iframu&lt;/h1&gt;
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    &lt;script type="text/javascript"&gt;
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&lt;/html&gt;</pre>