You can either use a loop or use a function that uses a loop.
Some libraries, like jQuery, offer their own functions (that use loops).
Using a loop is not a bad thing.
You can keep your code pretty (and organized) by putting the loop in a function.
var stringArray = [ "one", "two", "three" ];
var searchTerm = "two";
if (contains(stringArray, searchTerm)) {
alert("found it");
}
function contains(someArray, someTerm) {
for (var i = 0; i < someArray.length; i++) {
if (someArray[i] === someTerm) {
return true;
}
return false;
}