Add a chat button to my post item page

Hello I would like for someone to add a "Send Message" button on my listing page.. This link i am sending you is a link for the template I am using. Please understand this is only a sample. But this would be the listing page that i am wanting a chat button on that would connect to my message box. [login to view URL] Here is the issue I do not want a send inquiry on the page because I do not want people to have to exchange their private email addresses. I would like all contact to stay on the site for security reasons. So i am looking for a "Send Message" to be placed on the pages of all listings that the A potential buyer can contact the seller of the item without having to give there email address to have contact. I would like for this button to lead them to a pop window that allows them to type in their question. this question then goes into the sellers inbox. If the seller is online he should be immediately notified. The seller will get a email notification and if he is online then the seller should get a icon that lights up just like on fb that there is someone that has a question. So every page that has an item being sold must have a "Send Message" that opens up a message box for the buyer to send the seller of that particular item a message. The "Send Message" button opens a message box for the person to type into. That message after they press the "Send" button will go to the sellers inbox. The seller then notified by email and also by a notification on the site. Will look at the message and respond back to the buyer, the buyer then will receive e a notification that there is a message for the buyer. Please type 48595890 if you can do this.