How to put a line over a div at a specific place?

I am using a javascript based calendar. I am supposed to introduce a line in it marking today's date. I was able to achieve it for cells that are expanded. But I cannot introduce a line when the cells are collapsed. The reason is that, during the collapsed case, the row is one full div as opposed to seven individual cells.

You can开发者_如何学Go see in the above image there is an ash Line running indicating today's date. But not for the collapsed times. What is the best way to achieve a line in between them?

Is it required that those collapsed ones be only one div or can you make them into seven divs and get rid of the borders?

The idea being that making them separate divs then allows you to put in thicker borders (assuming that is how you are generating the line).

Alternatively you may be able to use a relatively positioned DIV for the marker line and do some calculations on where it needs to be and then have it floating over the rest of your content. This way it would not matter what layout the stuff underneath was. This does rely on there being a relatively easy way to calculate the desired position (I'm assuming its not always just before the last day).