文本编辑器（ckeditor）的Javascript验证无效

I have made the coding of javascript validation for editor(i am using ckeditor).It is not working properly.i.e when i am going to submit the form at first the alert box is coming as the editor is empty but when i am adding some content and going to validate it ,still the alert box is coming.After it everything goes fine.But i want that the alert box will come once ,when the editor field is empty.So please suggest me.Below is my coding.Thank you.

<script type="text/JavaScript">
 function validate()

 { 

        var descrip = document.getElementById("description").value;

if(descrip  == "") {
        alert("Please Enter partner description");
         document.getElementById("description").focus();
         document.getElementById("description").style.borderColor="#fd00d6";
         return false;  
    }

  }
</script>
<script src="ckeditor/ckeditor.js"></script>

<form role="form" action="" method="post" enctype="multipart/form-data" onsubmit="return validate();">

    <div class="box-body">


        <div class="form-group">

            <label for="exampleInputEmail1">Partner Description</label>

            <textarea id="description" name="description"   rows="10" cols="80" class="ckeditor" ><?php echo $_REQUEST['description']; ?> </textarea>

        </div>

    </div>
    <div class="box-footer">

        <button type="submit" class="btn btn-primary" name="add_partner">Submit</button>

    </div>
</form>

After reserching a lot ,finally i have found the solution for it. Instead of using

var descrip = document.getElementById("description").value;

if we use

var get_desc =  CKEDITOR.instances['description'].getData();

Then we can get the accurate result of that text editor associate field. when editor is empty ,it will return null ,otherwise the the editor value it self. Here we can simply get the (get_desc) ,according to which we can validate the field. Its working fine.I have tested it .Thank you.