How to create browser Extension ? compatible with IE, Chrome, Firefox , Safari and Opera?

I want to make my own extension so people who are using my website for every purpose they get easily things in same window.

I tried to install and build a Alexa Toolbar But it not support further extension which I want to put within like wise.

• Direct Website Login
• Facebook Post Sharing on (Fan Page) [ same for other social network ]
• Facebook Group Comment View [ same for other social network ]
• Logged User Social Account Account

and such type of other functionality I want to include for the Web development.like

• CSS Reloder
• Color Schemer
• Ruler
• Google page Speed
• Alexa View

Thanks In Advance. [Note :- Please Comment only if you are sure about your code are working fine because It wast time from both side!]

If you are looking to develop an extension to work on all the browsers, you can check if Crossrider fullfills your needs. If their framework's api can do what you want, you can save some time on developing an extension for each individual browser.