Thus, unless you have been granted a license to use that content by the copyright holder, you have no legal right to copy it to your own web site.
Companies have valid reasons for wanting to control where their ads are posted:
- They don't want to be overwhelmed by inquiries from unqualified applicants.
- They want to be able to remove the ad when the job has been filled.
- They want to protect their brand by posting their jobs on sites that are well-known and trusted.
You're not doing these companies a favor by re-posting their job ads without their consent.
So you can expect the companies to file DMCA takedown notices against your web site (or to threaten you personally with legal action) if they find out that their ads have appeared on your site.
And by copying FB's content to your own site, you're also presumably violating FB's terms of service, and could have your access to FB revoked.