Lua :)

local function fallback(a, b) return a + b end
      
-- web.require for loading modules from URLs
-- first argument of web.require is the name of the module, second is the (possibly relative) URL
-- we pcall it in case web.require doesn't work (e.g. if page is opened directly from filesystem)
local status, gcd = pcall(function() return web.require("gcd", "./gcd.lua") end)

gcd = status and gcd or { gcd = fallback }

-- lcd.lua contains `require("gcd")`. it works since the the previous web.require named that module "gcd"
local status, lcd = pcall(function() return web.require("lcd", "./lcd.lua") end)

lcd = status and lcd or { lcd = fallback }

-- blah blah. some example code:
local function td(content)
  return "<td>" .. content .. "</td>"
end
        
local function row(a, b)
  return "<tr>" .. td(a) .. td(b) .. td(gcd.gcd(a, b)) .. td(lcd.lcd(a, b)) .. "</tr>"
end

local html = {
  [[<ul>
<li><a href="https://www.lua.org/"><img src="./lua-logo.gif" alt="Lua"></a></li>
<li><a href="https://github.com/Glorp/webby-lua">in the browser</a></li>
</ul>]],
  "<table><thead>",
  "<table><thead>",
  "<tr><th>a</th><th>b</th><th>gcd(a, b)</th><th>lcd(a, b)</th></tr>",
  "</thead><tbody>"
}

local i = 0
while i < 10 do
  i = i + 1
  table.insert(html, row(math.random(2, 20), math.random(2, 20)))
end
        
table.insert(html, "</tbody></table>")
        
web.html(table.concat(html))

autorun: