Set the site display language based on browser's language on Drupal 6 and 7

drupal language

The other days I needed to have the language of a Drupal 6 site changed based on the user's browser language. This didn't seem to be such a daunting task but I thought that probably there is a module that does this already. Well I didn't found any module and I said to myself that this is something that I had to code although I could not believe that no one else needed this functionality until now...

Font size in all browsers

Having problems with font sizes in some browsers? Here's the deal...

Resizing fonts is very useful when creating web pages, but sometimes the output is not as expected in all browsers, especially Internet Explorer. Why? Because IE doesn't agree resizing with pixels like other browsers: e.g.

div {font-size:25px;}
h4 {font-size:14px;}

they work perfectly in all browser but not in IE. Internet Explorer uses em units. So,
1em equals 16px