Javascript for Squarespace website

We run a website on the Squarespace CMS. We require a javascript coder to write us a script to accomplish the following... We have set up a navigation menu to help readers navigate to topics of interest. Some of these topics are placeholders that currently don't contain any articles, but will do so in the future. At present, if a reader clicks a placeholder link, the Squarespace CMS generates a page with the following text: "Page Not Found The page /content/tag/cyberbullying-services could not be located on this website. We recommend using the navigation bar to get back on track within our site. If you feel you have reached this page in error, please contact a site operator. Thank you! Return to the Front Page »" We would like this page to say the following instead: "No Articles Found There are currently no articles available under the topic you have searched for. Return to the Front Page »" Our website is at [login to view URL]