Untitled

<html>
<head>
<script src="https://cdn.ckeditor.com/4.8.0/full-all/ckeditor.js"></script>
<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS_HTML"></script>
    <script>
     function onSubmit(){
        var data = CKEDITOR.instances.editor1.getData()
         document.getElementById("show").innerHTML=data
    }
</script>
</head>
<body>

<form action="#" >
<textarea rows="20" cols="70" class="ckeditor" id="editor1" name="test1">
</textarea>
 <input type="button" value="save" onclick="onSubmit()" >

</form>
<div id="show" id='ed2'></div>

    <script>

        CKEDITOR.replace( 'editor1', {
            extraPlugins: 'mathjax',
            mathJaxLib: 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.0/MathJax.js?config=TeX-AMS_HTML',
            height: 320
        } );

        if ( CKEDITOR.env.ie && CKEDITOR.env.version == 8 ) {
            document.getElementById( 'ie8-warning' ).className = 'tip alert';
        }

    </script>
 </body>
 </html>