I would like to create wordpress plugin that will display "quote of the day". I have an external website that hosts a lot of quotes and I would like to use them in my wordpress quote plugin.
I was told that wordpress doesn't allow you to use iframe. The random Wordpress quotes plugins I have seen so far are just displaying manually inserted quotes not quotes from some external websites.
Edit: My website is using asp.net and there is a rss feed there.
I would parse the RSS feed of the quote website (assuming that it has one) and display the quotes that way. You should abe able to use WordPress' native RSS support to do this. Check out an article on it here.
The Wordpress site has a good Plugin Guide that will explain the basics, and provides links to other example/tutorial sites.
To gather the "quote of the day", you've got a couple of options. First and easiest would be to grab the quote via their RSS feed if available. Then, a simple script would allow you to place it where you'd like.
If the site doesn't provide an RSS feed, you'll need to implement some sort of screen scraping script to grab the relevant portion of the page you want. You didn't mention what language you'd like to use, but there are plenty of screen scrapers out for many different languages.
If you create (or find) some php code that can get the info you need you can create a widget to display it on your site in a widget. You can use widgetifyr.com to wrap the php code in a widget it created for you. Once you create the widget you can use it on your web site just like any other widget.