Ask HN: alternative to 'mailto:'?

The current version of 'mailto:' (http://www.w3schools.com/html/tryit.asp?filename=tryhtml_mailto) is broken. For one, it works in firefox but not in IE or chrome. And two, it only gives options for gmail and yahoo mail.

I'm lookin for an alternative that will take the user to his email login page (just like 'mailto:' does) but across all browsers. The closest options I've come across are the 'email' buttons in sharing widgets (sharethis.com for example), but my split-tests show that users don't like to use them since they requires the user to enter their email login info into a 3rd party app.

Any suggestions? Is it possible to modify these 3rd party widgets to send a user to his email login page rather than having him login in the app directly?