Number your index cards in the upper right-hand corner. if you number all of your bibliography cards in the order in which you find the sources you'll ensure that you don't forget any when constructing your final bibliography.
Start by writing the author name of the online article, if any author is credited. Write the last name first, and position it in the upper end of the card on the left-hand side.
Add the title of the article, if any. If the article doesn't have a title, write the section of the website on which the information appears.
Starting with the next line of your index card, indent about five characters to the right of the first line, and keep all subsequent lines indented that far, aligned on their left. Write "Online at" followed by the URL (web address) of the article.
Finish by writing the date of publication, if given, preferably in DD Month YYYY format (for example, "12 March 1984").