小编ITG*_*uru的帖子

function format() {
  var text = document.getElementById("formatArea").value;
  text.replace("\n", "<br/>");
  document.getElementById("resultArea").value = text;
}

<textarea rows="20" cols="80" id="formatArea">
</textarea>


<textarea rows="20" cols="80" id="resultArea">
</textarea>

<button onclick="format()">Click to create HTML breaks</button>