Question: I have a file with a different number of rows for every "unit", and I'd like all the units to have the same number of rows, by adding the right number of empty rows per unit in the data. 

For example:

```
data list list/ unit serial someData.
begin data.
1 1 54
2 1 57
2 2 87
2 3 91
3 1 17
3 2 43
end data.

```

what i'd like to get to is this: 

```
1 1 54  
1 2  .  
1 3  .  
2 1 57  
2 2 87  
2 3 91  
3 1 17  
3 2 43  
3 3  .  

```

I've worked with simple workarounds, for example `casestovars` => `varstocases` (keeping nulls), or preparing a base file with all the lines with unit names and serials, and then matching it with the data file so I end up with all the lines and all the data.  

Could anyone suggest a more direct (\elegant\efficient\simple) approach?
Thanks!

Answer: 
use `target="_blank"` attribute in your anchor tag, like

```
<li><a target="_blank" href="#tab_one">Tab1</a></li>

```
You can set the id of tab two in href tag of anchor element. 

```
<div><a href="#tab_two">Click here to open tab 2</a></div>

```