display user input using ajax in wordpress

I don’t have enough reputation to comment. Try giving the datatype to the ajax call maybe this is due to json error.

Try adding datatype in your ajax as html for testing, then you can get into working path from these

   $.ajax({
     type: 'POST',
     url: ajaxurl,
     dataType: "html",
     data:{"action":'InsertIntoDB',message:text},
     success:function(msg){
         alert(msg);
     }

Also just try ajaxurl in the url field instead of MyAjax.ajaxurl even specifying datatype is not helping otherwise don’t mess up with the url. Try the above and let me know what response you get in firebug.