How to make alert after adding a "wissel"

In my code you see there wil be an alert when you have 3 "wissels" but i want to have a alert when you try to add a 4th "wisse".

function addWisselTeam1(){
    aantalWisselsTeam1++;

    document.getElementById("aantalWisselsTeam1").innerHTML = aantalWisselsTeam1;    

    if(aantalWisselsTeam1 >= 3){
        alert("U heeft nu 3 wissels gebruikt");

        aantalWisselsTeam1--;
    }
}