For example follow simple HTML code display "Stack Overflow" in web browser. My question is what is the default font family and how can I check it? (Are there any specific way to check this?)
<body> Stack Overflow </body> 3 Answers
Here is an overview of default web browser fonts:
You can also download a browser plugin to select some text and get the font name (e.g Font Finder for Firefox)
Each browser has a default stylesheet, e.g. this one from Chrome:
Alternatively, just Inspect the element, and look at the computed tab.
In browsers I use (Chrome, Opera, Firefox) default fonts are: Standard font: Times New Roman, Serif font: Times New Roman, Sans-serif font: Arial, Monospaced or fixed-width: Consolas (Firefox: Courier New).
