How to include external CSS file in html? 02-05-2017 08:33:04 CSS / Common 0 Bookmark(s) 419 View(s) With an external style sheet, you can change the look of an entire website by changing just one file. <!DOCTYPE html> <html> <body> <head> <link rel="stylesheet" type="text/css" href="mystyle.css"> </head> </body> </html> Note :- src - location of js file.