Pixel Border and Percentage width in Proportion

Question

I think I might already know the answer to this one but I need a sanity check!

Say I have

#gridtest{
width:590px;
}

I could change the

Answer 1

If possible, depending on your design, what I like to do is put the border as an absolute div with a width of 3px ( for example ) and a height higher than its parent div. I then set overflow hidden on the parent div.