Hey there! :)
I'm available immediately, and seeing as JavaScript is my specialty, I'd be happy to help. Could you send me a link to the page that you need the text hidden on, as well as provide a bit more specifics about what text would be hidden and when?
As for the standard "about me" formalities, I've been using JavaScript both professionally and as a hobby most of my life, and while I've only recently joined Freelancer.com, I've been freelancing as a JavaScript expert for quite some time now. By all means, feel free to check my profile for a few testimonials from past clients, as well as to get to know a bit more about me.
With that out of the way, I'd love to hear from you as soon as possible. Toss me a reply so we can get started right away! I look forward to working with you. :)