How to check id is exists or not using jQuery?

In this article, I will show you
how to check the element id is exists or not using jQuery. It probably will
help in dynamic generated HTML elements, this simple example, check whether the
id is there or not like this, 

<script type="text/javascript">

function savecomment() {

if ($("#txtcomment").attr("id")) {

         // ...            

 } else {

         // ...

        } 

}

</script>

<textarea name='textarea1' id='txtcomment' placeholder='Add acomment...' autocomplete='off'

 required='required' class='form-control custom-control' rows='3' style='resize:none'>

</textarea>