Capturing form values with javascript (not working in Safari!)

Question

Hi
I'm working on a site and I need to be able to take the values of one form (that the user has entered) and use them to populate a second form (more details) in the appropriate input boxes. This works on all browser except Safari. It seems to me a javascript problem (as getElementById does not work properly) but I'm not entirely sure. The code I use to grab the form elements is as follows:
obj = $('formslider".$this->id."');
obj.getElementById('registerfirstname".$this->id."').value = callbackfirstname".$this->id.";
obj.getElementById('registersurname".$this->id."').value = callbacksurname".$this->id.";
obj.getElementById('registeremail_addr".$this->id."').value = callbackemail".$this->id.";
obj.getElementById('registertelephone".$this->id."').value = callbacktelephone".$this->id.";
obj.getElementById('registerrequest_type".$this->id."').value = requesttype_callback".$this->id.";
This basically takes the values of the "callback" form and places them into the appropriate input boxes of the "register" form. However it seems to lose the values when moving to the next form. Please note, I am not refreshing - I am using Ajax to change the form so new content simply replaces an existing content, not transfering to another page. I use Sessions so it shouldn't forget the values.
Can anyone help? It's quite an important thing as I need to migrate hidden form inputs too which are needed for this particular request system.
Thanks
Michael

Answer 1

I'm seeing this same issue in Mavericks, 10.9.2.  Althought JavaScript is enabled in Safari, it just doesn't work, for any pages.
I've tried different user accounts, including a new account, on the same machine, but they all do the same thing, so it's a machine-wide issue.
I have plenty of other Mavericks machines, including my own, where it is working just fine, however, with the same settings.