You can do this through .NET interface, it is very complicated.
Google : .NET DLR javascript
You can call .NET methods from labview and there is an existing DLR implementation of javascript. The least to vapour is IronJS.
Download the libraries, force labview use the .NET 4.0 or higher and try to use it.
Since you mentioned "small javascript", much less painfull would be to rewrite it in labview. If you are trying to mimic some javascript code online you didnt develop, you can use tools to breakpoint and probe it by tools in browsers. Firefox has firebug. I used it when I was converting a very difficult mathematic conversion between C and javascript.
