nueva línea html
<!-- Code by Scratchy -->
<!-- Twitter: @S_cratchy-->
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<br>
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Scratchy
<!-- Code by Scratchy -->
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<p>
Will Mateson<br />
Box 61<br />
Cleveland, Ohio<br />
</p>
//setting this css style solving problem with new line in textContent
h1.setAttribute('style', 'white-space: pre;');
//add \r\n in text everywhere You want for line-break (new line)
h1.textContent = "this is line one \r\n and this is line 2";
<span style="white-space: pre-line">@Model.CommentText</span>
<body>
<p>This is paragraph #1</p>
<p>This is paragraph #2</p>
<p>This is paragraph #3</p>
</body>