Assign Style And Class

I've got this pice of code:

var ourDiv=document.getElementById('cretor);
var t=document.createElement('table');
var tb=document.createElement('tbody');
t.style.border=Ǝpx groove blue'

var tr=document.createElement('tr');
var td=document.createElement('td');

Then I append and everything... My question: I want to assign a class and a style,
the class named "asdf" and in the style, a "border-top-width of 35px" and a "border-top-style of outset,