If you want to multiple rows of html content via jQuery using append function and at the end of the line put slash(\) for sequence line.
$("#test").append("<textarea id='txtcomment' style='width: 100%;cursor:pointer;'\
rows='4' class='input textarea' required=''autocomplete='off'></textarea>\
<inputname='submit' type='submit' id='submit' class='submit'\
value='SubmitComment'>");