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let x = 5;//Variable globale
let y = 10; //Variable locale
alert(x + y); // = x + 10
let x = 100;
alert(x); // = 100
/*Décommentez le code pour l'exécuter
portee1(); // 5 + 10 = 15
x = 20; //On modifie la valeur dans x global
portee1(); // La dernière valeur connue de x (20) est utilisée
portee2(); // 100