How to get the size of the browser inner space if it were maximized in pixels through javascript

I need to kno开发者_JS百科w the client available screen size, I mean the size of the browser inner space if it were maximized in pixels. I need some code that works on both IE and Firefox at least.

Thanks in advance

screen.availWidth/Height should work in most browsers.

alert(window.screen.availWidth);

• Mozilla Developer Network docs
• MSDN docs