Problem with selecting multiple tables and access trough '[x]'

Problem with selecting multiple tables and access trough '[x]'

hi

i'm selecting tables in my page with the following selector:
  1. $(".mytables")            // this finds 4 tables
Now the following code line is giving me error message : 'the css function/method is undefined...'
  1. $(".mytables")[0].css('property', value)
And the following lines are working correclty:
  1. $(".mytables").fisrt().css('property', value)
or
  1. var table = $(".mytables")[0]
  2. table.css('property', value)

Why this behavior ?? Where is the difference ??