Check out example codes for "replace all br tags within node with paragraph opening and closing tags". It will help you in understanding the concepts better.

Code Example 1

//My suggestion will be to split the text by <br>:

var lines = content.split("<br>");

//Now you can wrap each line in a <div>:

var newContent = "";
for(var i=0,l=lines.length;i<l;i++){
     newContent += "<div>"+lines[i]+"</div>";

}

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