loop:
while(true){
var sport = prompt("What sport do you play? (Baseball, Football, Soccer, or Track)").toLowerCase();
switch (sport) {
case "baseball":
field = "Field 1";
break loop;
case "football":
field = "Field 2";
break loop;
case "soccer":
field = "Field 3";
break loop;
case "track":
field = "Field 4";
break loop;
default: alert("Please enter a valid sport");
}
}
or
var field;
while(true){
var sport = prompt("What sport do you play? (Baseball, Football, Soccer, or Track)").toLowerCase();
if(!sport || /^(baseball|football|soccer|track)$/.test(sport)){
field = "Field " + ("baseball|football|soccer|track".split("|").indexOf(sport)+1);
break;
}else{
alert("Please enter a valid sport");
}
}