“Browser Mode”, “Document Mode” and “Compatibility View” in Internet Explorer.

Subject: - “Browser Mode” , “Document Mode” and “Compatibility View” in Internet Explorer.  

Already:-I was opening a site (Intranet) on Internet Explorer version 8, but somehow it was opening in Browser Mode 8 and Document Mode 7. So it was not opening properly. Then I changed the Document Mode to 8 and everything was working.

Problem: -So I have a dilemma that what is this all about. Why are we having the kind of options?

1. - Browser Mode
2. - Document Mode
3. -CompatibilityView.

Please let me know what is Browser and Document Mode and one more thing which I have seen, it is Compatibility View. What is this all about?

Please provide some references which can enlighten Browser Mode, Document Mode and Compatibility View.

I will be thankful to you.