I am wondering how can I open the send SMS application by using a web control of a HTML5 page on Android and iPhone. I want to use the device native SMS sending app, with a prepopulated value from the web.
Further to other answers I can confirm that smsto:555:bodytext does not work on an iPhone running iOS5.
What does work (and I've tested it) on Android is the format:
sms:444?body=hello
Example:
<a href="sms:444?body=hello">Tap to say hello!</a>
On iPhone the ?body=hello will prevent it working at all, and you should use just sms:555 instead.
sms:555
Example
<a href="sms:444">Tap to text us!</a>