I'm using jquery mobile datepicker 1.0a4.1. but I can't changed minDate in any page. I created two datepicker. I want when I selected a dete in first datepicker,the second datepicker's mindate should be this selected date. How can I do it?
That is way obsolete, and most likely not compatible with the current jQuery Mobile. It was an experiment that was part of jQuery Mobile 1.0a4 - which was an alpha test pee-release version of th jQuery Mobile.
Alpha tests are just that - tests. It never made it into jQuery Mobile officially, and I am afraid you are on your own (and advice from other here) to find a suitable datepicker.
Unless you need the date formatted to a certain standard, you can just use the device native date picker. Assuming you do need a certain format, I would find a different date picker. I know there has been some luck using the JQuery UI Date Picker, but it's not officially supported.