<!--Required jQuery Library File -->
<script src="jquery.min.js"></script>
<textarea id="detail" placeholder="type something..!"><
/textarea>
<button onclick="showText()">Click Me</button>
<script>
function showText(){
alert($("#detail").val());
}
</script>
<br>
<span><b>Comment:</b> Click on button to show 'textarea' element
text</span>