Control client-side Java-script using VB6 to push Button

Question

I want to automate stock trading with a broker who uses client side JavaScript.  I want to respond using VB6/VBA/EXCEL interface to:  read variables, write into boxes, click buttons, etc. in the JavaScript to enter trades and extract any text files that would normally appear on my monitor.  How do I do that using VB6 software?   Thanks.