 <p>You have not specified how much rows should be added to the textarea but I hope this answers your question. This code will work only if you have already set the default number of rows of your textarea in HTML, through the <code>rows</code> attribute.</p> <pre><code>$(function () { var rowsAdded = false; $("#myTextarea").keyup(function () { var textarea = $(this); if (textarea.val().length &gt; 52 &amp;&amp; !rowsAdded) { textarea.attr('rows', parseInt(textarea.attr('rows')) + rowsToAdd); // replace rowsToAdd with the number of rows to add to the textarea rowsAdded = true; } }); }); </code></pre>