ECMS-6509 : first modification : keep form.submit for IE8 or lower, but ...

...use ajaxPost for IE > 8 or not IE. Second modification : if IE8 or lower, get backto parameter for request, and put it as parameter of the form action. Then after the submit, the backto parameter will be stil usable


To know if we use IE8 and lower,  I found informations here : http://tanalin.com/en/articles/ie-version-js/