On page is on website and off page is using external links to improve your site’s ranking. Hal Smith
On Page SEO is basically conducted over the web page i.e. inserting the right SEO optimized content, Meta Tags, Title Tags, Meta Description etc. however when it comes to Off Page SEO, it literally means link Building. Link building normally includes Forum Posting, Blog Commenting, Article Submission, Directory Submission etc.
Basic on-page SEO implies that you use your keyword in:
Image Alt Tag
Off-page SEO is all about building links that point back to your site (aka backlinks)
Web 2.0 Properties
Hi meenu you can get full information about SEO.
On Page Optimization
Off page optimization
On page SEO is waht is on your page. Your page structure. Your semantics. Keyword density. Long tail keywords, and so on.
Off Page Seo is backlinking. Any link from other site to your site is off page seo.
On-Page SEO refers to anything you can do to improve your own website like: Meta-tags, content, navigation, cleaning up errors, internal linking, alt tags, heading tags, sitemaps, etc. Off-Page SEO refers to what can be done outside of a website to maximize its performance for specific keywords/phrases by acquiring backlinks.
On page optimization includes accurately indexed contents, keywords are being determined, and H1 and H2 tags are added whereas off page optimization includes submitting website to most important directories, social bookmarking websites, link building etc.