A radio stream through html and edit volume with javascript? Possible?

[0oRichard]

local bool = true
local function Radio(ply, msg)
    emsg = string.lower(msg)

    if (emsg == "!radio") then
        LocalPlayer().Panel = LocalPlayer().Panel or NULL
		local Derp = LocalPlayer().Panel
         if  !bool then
             if Derp:IsValid()  then 
			 Derp:Remove()
			 end
            bool = true
            chat.AddText("Radio Off")
        else
            chat.AddText("Radio On")
            new_panel = vgui.Create("HTML")
            new_panel:OpenURL("http://ng.net84.net/radio/Radio_ingame.html")
			new_panel:SetVisible(false)
			LocalPlayer().Panel = new_panel
            bool = false
        end
        return true
    end
end

hook.Add("OnPlayerChat","Radio",Radio)

First of all my javascript knowledge is at a nil atm (i'm reading up on it). I know javascript can find html elements and change values. So how would i go on about creating a "!volume amount" command that changes the volume of the stream i provided in OpenURL? Feel free to look at the source and please give me some pointers on where i should get started. All the confusing javascript is provided in the OpenURL bit of my script.