Url trigger -> Applescript with parameter

I would like to create a macro who will be trigged by local URL and pass a parameter to an Applescript.

This is the trigger URL
http://127.0.0.1:4490/action.html?macro=4A91C4B8-CAC0-4850-B37B-6F1F0F0619E2&value=123456

This is the macro:

Triggered by any of the following:
Via Public Web Access
Will execute the following actions:
Set Variable “var” to Text %TriggerValue%
Execute AppleScript
Tell Application "Keyboard Maestro Engine"
if variable var exists then
set myTestString to get value of variable var
end if
end tell

But this doesn’t work. How I can pass the value “123456” to an applescript?

See Using Keyboard Maestro Variables in an AppleScript.