This is the way markdown was meant to be used. Definitely putting this on the list of things to add for posterous... It can't possibly be the default editor since WYSIWYG is what everyone expects at the end of the day, but for power users this is really going to move the needle on really dead simple markup.
This article explains iframe-to-iframe communication, when the iframes come from different domains.
Great article, and details a really cool hack to get cross-domain frames to work. It's one dark recess of web technology that is actually quite useful, but is rarely explained in such proper and interesting detail.
Epic win. First, download the free version of Visual Web Developer 2008 here. Install it. Enjoy waiting twenty minutes. Get a cup of coffee. Don't sit there waiting for the worst out of box experience ever, whatever you do.
Next, go to Internet Explorer's Internet Options and set Internet Explorer as your default browser. I know, terrible, but you gotta do it -- otherwise VWD2008 tries to use Firefox, Chrome or your other superior default browser and you lose the ability to debug IE7 in all of its awful putrescence. While you're in Internet Options, you should also de-select disabling script debugging and enable debug messages in the Advanced tab. Now you have to create an Empty Web Project by clicking New > New Website. Now click Debug > Start Debugging. It'll open a new IE window pointed at localhost, but just fire up whatever to-be-debugged website in that window. Awesome. Now any errors should drop you into the VWD2008 debugger. ROCK ON.
Recently while writing some features for Posterous, I ran into a super simple but insanely annoying bug where IE fails to properly pick up id and name fields when creating new DOM elements in JavaScript using document.createElement().
Internet Explorer completely fails to add created DOM elements to the lookup table of named elements as targets. If you generate an iframe and want to POST to it from your programmatically generated FORM tag (by setting TARGET="your_new_element_name"), you're out of luck and IE will try to create a new window instead. InnerHTML to the rescue. The abomination of standards that is innerHTML works pretty well across all browsers. John Resig is so right when he says the DOM is a mess. Thank god for things like jquery.