css on same named form fields
===

so I have multiple forms on a page (don't know how many, created by php in an array).  Each one is simple and contains a number of fields, each with a name='fieldname'.

Now in the CSS I have:

form.sidemenu input[name=fieldname] { width: 40px; }

This works fine on the first instance of the form, but it doesn't have any effect on the appropriate fields in the rest of the forms.  I've now tried replacing this with specific classes in each input field (input name='fieldname' class='fieldname'....) and replaced form.sidemenu input.fieldname { width: 40px; } and still no luck with the subsequent ones, although the first form works fine.  

This is on Chrome Canary and Safari on OSX Lion, both behaving the same.