create a conditional back button...how?

[BobInIndy]

I am using a google form in an iframe on a web page with a typical back button such as this:
INPUT TYPE="button" VALUE="Previous Page"
onClick="history.go(-1);return true;"

The problem is, if they press the back button without submitting the form, the code that works is:
onClick="history.go(-1);return true;"
(ie the google form)

If they press the back button after submitting the form, the code that works is:
onClick="history.go(-2);return true;"
(ie the google form, the thank you page)

But, it is 1 button. So I need an html conditional, that something like:
If pagetitle="Google_Form.html" then
onClick="history.go(-1);return true;"
else
onClick="history.go(-2);return true;"
end if

Can someone give me the code to do this?
Don't assume I know much....

Thanks
bob

[phurien]

You should probably do a javascript funtion. Have onClick="javascript:goBack(); return true;" then make the function.

function goBack()
{
 // put your if statement here.
}