Add a new funcion to a script code page

Hi there! this is a script code that can be added more than once per web page, and i want to add for example google analystic inside in this script but when it is installed more than once in one website it will load google analystic more than once and i don’t want this, i want google code to get loaded only once even if this script code is installed many times in one web page this is the script code /////

//// For any questions i am available