Script : <script type="text/javascript"> function transferText() { document.getElementById("textareaInput").value += document.getElementById("txtInput").value; } </script> HTML: And update the HTML code like this : <input id="txtInput" value="text" /> <input type="button" onclick="transferText();" /> <textarea id="textareaInput">Lalala</textarea> HTML: Update the input id, textarea id and the button onclick event. Good luck