jQuery / HTML scrolling behaviour

So I have a page that is开发者_JAVA技巧 split into 2 columns. The left column there are expandable forms that are quite long to ask the user optional product preferences. On the right side of the page there is a much shorter, 'contact details' form. The contact details form is mandatory.

The behaviour idea is that as the user scrolls down to complete the left column optional forms, the page will only scroll the left column - the contact details forms displayed in the right column stays in place to avoid a big gaping white space where the right column is empty. I'm having trouble implementing this and I haven't found a solution yet or any examples of pages with this split column behaviour online.

Any advice / suggestions / examples online? Thanks!

User overflow:scroll for the left column.