Small peice of coding

Hi I need to get a button to stay in a fixed position on a website so when you scroll down the page it stays in a fixed position on the right of the screen the code is below that i have like the button here www.targetcapital.co.uk its for php


live chat for website


var __lc_buttons = __lc_buttons || [];
__lc_buttons.push({
elementId: 'LiveChat_1343305726',
skill: '0'
});